diff --git a/.clang-tidy b/.clang-tidy
index b77eb7afc9..069842df90 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -9,7 +9,7 @@ Checks: '
   -bugprone-easily-swappable-parameters,
   -bugprone-macro-parentheses,
   -bugprone-narrowing-conversions,
-  -bugprone-unchecked-optional-access,
+
   -modernize-use-trailing-return-type,
   -modernize-avoid-c-arrays,
   -modernize-use-nodiscard,
diff --git a/.github/workflows/linux-eic-shell.yml b/.github/workflows/linux-eic-shell.yml
index 824bafa87a..7e6f9af9ba 100644
--- a/.github/workflows/linux-eic-shell.yml
+++ b/.github/workflows/linux-eic-shell.yml
@@ -251,11 +251,12 @@ jobs:
       with:
         platform-release: "${{ env.platform }}:${{ env.release }}"
         run: |
+          git diff ${{ github.event.pull_request.head.sha }} ${{ github.event.pull_request.base.sha }} --name-only | tee changed_files.txt
           # reduce headers until diff is stable
           while [[ ${sha:-} != $(git diff | sha256sum) ]] ; do
             sha=$(git diff | sha256sum)
             echo $sha
-            iwyu_tool.py -p build $(git diff --name-only ${{ github.event.pull_request.head.sha }} ${{ github.event.pull_request.base.sha }}) -- -Xiwyu --verbose=3 -Xiwyu --no_fwd_decls -Xiwyu --cxx17ns -Xiwyu --mapping_file=${{github.workspace}}/.github/iwyu.imp -Xiwyu --regex=ecmascript | tee iwyu_fixes.log
+            iwyu_tool.py -p build $(cat changed_files.txt | grep -E '\.(cpp|cc|cxx|c\+\+)$' | paste -sd ' ') -- -Xiwyu --verbose=3 -Xiwyu --no_fwd_decls -Xiwyu --cxx17ns -Xiwyu --mapping_file=${{github.workspace}}/.github/iwyu.imp -Xiwyu --regex=ecmascript | tee iwyu_fixes.log
             fix_includes.py --blank_lines --nosafe_headers --reorder --separate_project_includes="<tld>" --keep_iwyu_namespace_format < iwyu_fixes.log
             git diff | tee iwyu_fixes.patch
           done
diff --git a/src/algorithms/tracking/ActsToTracks.cc b/src/algorithms/tracking/ActsToTracks.cc
index ce694ffc90..64485f3a35 100644
--- a/src/algorithms/tracking/ActsToTracks.cc
+++ b/src/algorithms/tracking/ActsToTracks.cc
@@ -97,6 +97,10 @@ void ActsToTracks::process(const Input& input, const Output& output) const {
       // Get the fitted track parameter
       const auto& boundParam = traj->trackParameters(trackTip);
       const auto& parameter  = boundParam.parameters();
+      if (!boundParam.covariance().has_value()) {
+        warning("Track parameters do not have covariance matrix, skipping track");
+        continue;
+      }
       const auto& covariance = *boundParam.covariance();
 
       auto pars = track_parameters->create();
diff --git a/src/algorithms/tracking/TrackPropagation.cc b/src/algorithms/tracking/TrackPropagation.cc
index 5582707da5..ed393ea76c 100644
--- a/src/algorithms/tracking/TrackPropagation.cc
+++ b/src/algorithms/tracking/TrackPropagation.cc
@@ -316,8 +316,16 @@ TrackPropagation::propagate(const edm4eic::Track& /* track */,
   m_log->trace("    propagation result is OK");
 
   // Pulling results to convenient variables
-  auto trackStateParams  = *((*result).endParameters);
-  const auto& parameter  = trackStateParams.parameters();
+  if (!(*result).endParameters.has_value()) {
+    m_log->trace("    propagation failed (endParameters not available)");
+    return nullptr;
+  }
+  auto trackStateParams = *((*result).endParameters);
+  const auto& parameter = trackStateParams.parameters();
+  if (!trackStateParams.covariance().has_value()) {
+    m_log->trace("    propagation failed (covariance not available)");
+    return nullptr;
+  }
   const auto& covariance = *trackStateParams.covariance();
 
   // Path length
diff --git a/src/benchmarks/reconstruction/tracking_efficiency/TrackingEfficiency_processor.cc b/src/benchmarks/reconstruction/tracking_efficiency/TrackingEfficiency_processor.cc
index ae89fbc66c..b6374cddd8 100644
--- a/src/benchmarks/reconstruction/tracking_efficiency/TrackingEfficiency_processor.cc
+++ b/src/benchmarks/reconstruction/tracking_efficiency/TrackingEfficiency_processor.cc
@@ -108,6 +108,10 @@ void TrackingEfficiency_processor::Process(const std::shared_ptr<const JEvent>&
     if (traj->hasTrackParameters(trackTip)) {
       const auto& boundParam = traj->trackParameters(trackTip);
       const auto& parameter  = boundParam.parameters();
+      if (!boundParam.covariance().has_value()) {
+        m_log->debug("Track parameters do not have covariance matrix");
+        continue;
+      }
       const auto& covariance = *boundParam.covariance();
       m_log->debug("{:>10.2f} {:>10.2f}  {:>10.2f} {:>10.3f} {:>10.4f} {:>10.3f} {:>12.4e} "
                    "{:>12.4e} {:>12.4e} {:>8.2f}",