diff --git a/core/src/main/kotlin/org/evomaster/core/output/service/RestTestCaseWriter.kt b/core/src/main/kotlin/org/evomaster/core/output/service/RestTestCaseWriter.kt
index 7870281982..d6d0a4881c 100644
--- a/core/src/main/kotlin/org/evomaster/core/output/service/RestTestCaseWriter.kt
+++ b/core/src/main/kotlin/org/evomaster/core/output/service/RestTestCaseWriter.kt
@@ -436,6 +436,7 @@ class RestTestCaseWriter : HttpWsTestCaseWriter {
                     "\"$path\""
                 }
 
+                //FIXME this should be same algorithm as in AbstractRestFitness
                 val idPointer = res.getResourceId()?.pointer ?: "/id"
 
                 val extract = extractValueFromJsonResponse(resVarName, idPointer)
diff --git a/core/src/main/kotlin/org/evomaster/core/problem/rest/data/RestPath.kt b/core/src/main/kotlin/org/evomaster/core/problem/rest/data/RestPath.kt
index ee7f7e2981..7d3901b8d6 100644
--- a/core/src/main/kotlin/org/evomaster/core/problem/rest/data/RestPath.kt
+++ b/core/src/main/kotlin/org/evomaster/core/problem/rest/data/RestPath.kt
@@ -329,7 +329,7 @@ class RestPath(path: String) {
                     gene.getViewOfElements()
                         .joinToString("&") { "$name=${encode(it.getValueAsRawString())}" }
                 } else {
-                    val value = encode(gene!!.getValueAsRawString())
+                    val value = encode(gene.getValueAsRawString())
                     "$name=$value"
                 }
             }
@@ -391,6 +391,12 @@ class RestPath(path: String) {
                         it.value.name == t.name && (it.value.scope == null || it.value.scope == RestLinkParameter.Scope.PATH)
                     }?.key
 
+                    /*
+                        TODO are these correct??? are we properly escaping?
+                        also, URI does not comply with RFC 3968... :(
+                        need more testing
+                     */
+
                     if(variable != null){
                         /*
                             reserved characters need to be encoded
diff --git a/core/src/main/kotlin/org/evomaster/core/problem/rest/service/CallGraphService.kt b/core/src/main/kotlin/org/evomaster/core/problem/rest/service/CallGraphService.kt
index 3f4e09a709..0565430881 100644
--- a/core/src/main/kotlin/org/evomaster/core/problem/rest/service/CallGraphService.kt
+++ b/core/src/main/kotlin/org/evomaster/core/problem/rest/service/CallGraphService.kt
@@ -65,7 +65,7 @@ class CallGraphService {
     /**
      * Check in the schema if there is any action which is a direct child of [a] and last path element is a parameter
      */
-    fun hasParameterChild(a: RestCallAction): Boolean {
+    fun isThereChildActionWithParameter(a: RestCallAction): Boolean {
         return sampler.seeAvailableActions()
             .filterIsInstance<RestCallAction>()
             .map { it.path }
@@ -81,9 +81,9 @@ class CallGraphService {
 
     fun resolveLocationForParentOfChildOperationUsingCreatedResource(create: RestCallAction): String? {
 
-        if(hasParameterChild(create)) {
+        if(isThereChildActionWithParameter(create)) {
             //simple case
-            return create.resolvedPath()
+            return create.resolvedOnlyPath()
         }
 
         /*
diff --git a/core/src/main/kotlin/org/evomaster/core/problem/rest/service/fitness/AbstractRestFitness.kt b/core/src/main/kotlin/org/evomaster/core/problem/rest/service/fitness/AbstractRestFitness.kt
index b2a39cc9ac..b4acf9696f 100644
--- a/core/src/main/kotlin/org/evomaster/core/problem/rest/service/fitness/AbstractRestFitness.kt
+++ b/core/src/main/kotlin/org/evomaster/core/problem/rest/service/fitness/AbstractRestFitness.kt
@@ -63,7 +63,10 @@ import org.evomaster.core.taint.TaintAnalysis
 import org.evomaster.core.utils.StackTraceUtils
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
+import java.net.URI
 import java.net.URL
+import java.net.URLEncoder
+import java.nio.charset.StandardCharsets
 import javax.annotation.PostConstruct
 import javax.inject.Inject
 import javax.ws.rs.ProcessingException
@@ -877,23 +880,41 @@ abstract class AbstractRestFitness : HttpWsFitness<RestIndividual>() {
                     it is or not a valid char.
                     Furthermore, likely needed to be done in resolveLocation,
                     or at least check how RestAssured would behave
+                    TODO update RestPathTest, check TODO there, once fixed
                  */
                 //it.replace("\"", "")
+                //FIXME outputFormat shouldn't really be used here
+                //FIXME in resolveLocation
                 GeneUtils.applyEscapes(it, GeneUtils.EscapeMode.URI, configuration.outputFormat)
             }
 
+        Lazy.assert { URI.create(fullUri).isAbsolute }
 
-        val builder = if (a.produces.isEmpty()) {
-            log.debug("No 'produces' type defined for {}", path)
-            client.target(fullUri).request("*/*")
+        val builder = try {
+            if (a.produces.isEmpty()) {
+                log.debug("No 'produces' type defined for {}", path)
+                client.target(fullUri).request("*/*")
 
-        } else {
-            /*
+            } else {
+                /*
                 TODO: This only considers the first in the list of produced responses
                 This is fine for endpoints that only produce one type of response.
                 Could be a problem in future
             */
-            client.target(fullUri).request(a.produces.first())
+                client.target(fullUri).request(a.produces.first())
+            }
+        } catch (e: Exception) {
+            /*
+                FIXME we need to solve this issue somehow, as location values might be invalid...
+                but i guess that should be done in resolveLocation
+             */
+            throw RuntimeException("""
+                Failed to build HTTP invocation. 
+                Resolved path: $path
+                Location header: $locationHeader
+                Resolved location: $fullUri
+                Error: ${e.message}
+            """.trimIndent(), e)
         }
 
         handleHeaders(a, builder, cookies, tokens)
@@ -1004,8 +1025,17 @@ abstract class AbstractRestFitness : HttpWsFitness<RestIndividual>() {
                 val id = rcr.getResourceId()
 
                 if (id != null) {
-                    location = callGraphService.resolveLocationForChildOperationUsingCreatedResource(a,id.value)
+
+                    //FIXME tmp fix. need to be handled properly, also in generated tests with test-utils-*
+                    val escapedId = URLEncoder.encode(id.value, StandardCharsets.UTF_8)
+                        .replace("+", "%20");
+
+                    location = callGraphService.resolveLocationForChildOperationUsingCreatedResource(a,escapedId)
                     if(location != null) {
+                        /*
+                            FIXME this case seems ignored in RestTestCaseWriter.handleLocationHeader.
+                            Need proper handling + E2E for all these cases
+                         */
                         rcr.setHeuristicsForChainedLocation(true)
                     }
                 }
diff --git a/core/src/main/kotlin/org/evomaster/core/search/gene/regex/QuantifierRxGene.kt b/core/src/main/kotlin/org/evomaster/core/search/gene/regex/QuantifierRxGene.kt
index 49ff6bfb5d..d6d5469404 100644
--- a/core/src/main/kotlin/org/evomaster/core/search/gene/regex/QuantifierRxGene.kt
+++ b/core/src/main/kotlin/org/evomaster/core/search/gene/regex/QuantifierRxGene.kt
@@ -200,7 +200,9 @@ class QuantifierRxGene(
         }
 
         for (i in 0 until other.atoms.size) {
-            if (!this.atoms[i].containsSameValueAs(other.atoms[i])) {
+            val x = this.atoms[i]
+            val y = other.atoms[i]
+            if (!x.possiblySame(y) || !x.containsSameValueAs(y)) {
                 return false
             }
         }
diff --git a/core/src/main/kotlin/org/evomaster/core/search/gene/string/StringGene.kt b/core/src/main/kotlin/org/evomaster/core/search/gene/string/StringGene.kt
index 8e3abbe0c4..8c05aa3aaf 100644
--- a/core/src/main/kotlin/org/evomaster/core/search/gene/string/StringGene.kt
+++ b/core/src/main/kotlin/org/evomaster/core/search/gene/string/StringGene.kt
@@ -822,9 +822,10 @@ class StringGene(
                       try {
                               toAddGenes.add(RegexHandler.createGeneForJVM(regex))
                               log.trace("Regex, added specification for: {}", regex)
-
                           } catch (e: Exception) {
                               LoggingUtil.uniqueWarn(log, "Failed to handle regex: $regex")
+                          } catch (e: java.lang.StackOverflowError){
+                              LoggingUtil.uniqueWarn(log, "Failed to handle regex, as it gives a stack overflow error: $regex")
                           }
                       }
 
diff --git a/core/src/test/kotlin/org/evomaster/core/parser/RegexHandlerTest.kt b/core/src/test/kotlin/org/evomaster/core/parser/RegexHandlerTest.kt
index e98878b4f7..ef41b38b14 100644
--- a/core/src/test/kotlin/org/evomaster/core/parser/RegexHandlerTest.kt
+++ b/core/src/test/kotlin/org/evomaster/core/parser/RegexHandlerTest.kt
@@ -8,12 +8,20 @@ import org.evomaster.core.search.service.AdaptiveParameterControl
 import org.evomaster.core.search.service.Randomness
 import org.evomaster.core.search.service.mutator.MutationWeightControl
 import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertThrows
 import java.util.regex.Pattern
 
 internal class RegexHandlerTest{
 
+    @Disabled("Needs to hande lookahead in regex")
+    @Test
+    fun testLanguageTool(){
+        val s = "^((?iu)@.+)$"
+        RegexHandler.createGeneForJVM(s)
+    }
+
 
     @Test
     fun testCwaIssue(){
diff --git a/core/src/test/kotlin/org/evomaster/core/problem/rest/RestPathTest.kt b/core/src/test/kotlin/org/evomaster/core/problem/rest/RestPathTest.kt
index 3f6e247101..7ddf3d809b 100644
--- a/core/src/test/kotlin/org/evomaster/core/problem/rest/RestPathTest.kt
+++ b/core/src/test/kotlin/org/evomaster/core/problem/rest/RestPathTest.kt
@@ -1,6 +1,7 @@
 package org.evomaster.core.problem.rest
 
 import io.swagger.v3.oas.models.parameters.Parameter
+import org.evomaster.core.output.OutputFormat
 import org.evomaster.core.problem.rest.builder.RestActionBuilderV3
 import org.evomaster.core.problem.rest.data.HttpVerb
 import org.evomaster.core.problem.rest.data.RestPath
@@ -10,13 +11,44 @@ import org.evomaster.core.search.gene.collection.ArrayGene
 import org.evomaster.core.search.gene.wrapper.CustomMutationRateGene
 import org.evomaster.core.search.gene.numeric.IntegerGene
 import org.evomaster.core.search.gene.string.StringGene
+import org.evomaster.core.search.gene.utils.GeneUtils
+import org.glassfish.jersey.uri.internal.JerseyUriBuilder
 import org.junit.jupiter.api.Assertions.*
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.params.ParameterizedTest
 import org.junit.jupiter.params.provider.ValueSource
+import java.net.URISyntaxException
+import org.junit.jupiter.api.assertThrows
+import org.mockserver.configuration.Configuration.configuration
 
 internal class RestPathTest{
 
+    @Test
+    fun testFamilieBaSakIssue(){
+
+        val x = "/api/satsendring/kjorsatsendring?EMextraParam123=42/Trigget satsendring for fagsakene []"
+
+        assertThrows<Exception>{JerseyUriBuilder.fromUri(x).build()}
+
+        val path = RestPath("/api/satsendring/kjorsatsendring")
+        val q = QueryParam("EMextraParam123", StringGene("EMextraParam123", "42/Trigget satsendring for fagsakene []"))
+
+        val uri = path.resolve(listOf(q))
+
+        assertNotEquals(x, uri)
+
+        JerseyUriBuilder.fromUri(uri).build()
+
+        // check escape
+        //TODO update once fixing AbstractRestFitness
+        val y = "/api/satsendring/kjorsatsendring/Trigget satsendring for fagsakene []"
+        JerseyUriBuilder.fromUri(y).build()
+
+        val e = GeneUtils.applyEscapes(y, GeneUtils.EscapeMode.URI, OutputFormat.JAVA_JUNIT_4)
+        //FIXME spaces are not escaped
+        //assertNotEquals(y,e)
+    }
+
 
     @Test
     fun testNameQualifier(){