diff --git a/src/runtime/node.ts b/src/runtime/node.ts
index 3d327d9..36d616d 100644
--- a/src/runtime/node.ts
+++ b/src/runtime/node.ts
@@ -162,6 +162,10 @@ function resolveVirtualEnv(
  * Get the environment variable key for PATH (case-insensitive on Windows).
  */
 function getPathKey(env: Record<string, string | undefined>): string {
+  if (Object.prototype.hasOwnProperty.call(env, 'PATH')) {
+    return 'PATH';
+  }
+
   for (const key of Object.keys(env)) {
     if (key.toLowerCase() === 'path') {
       return key;
@@ -170,6 +174,20 @@ function getPathKey(env: Record<string, string | undefined>): string {
   return 'PATH';
 }
 
+function setPathValue(env: Record<string, string>, value: string): void {
+  setEnvValue(env, 'PATH', value);
+
+  if (process.platform !== 'win32') {
+    return;
+  }
+
+  for (const key of Object.keys(env)) {
+    if (key !== 'PATH' && key.toLowerCase() === 'path') {
+      setEnvValue(env, key, value);
+    }
+  }
+}
+
 const DANGEROUS_ENV_OVERRIDE_KEYS = new Set(['__proto__', 'prototype', 'constructor']);
 
 function createNullPrototypeEnv(): Record<string, string> {
@@ -674,8 +692,8 @@ function buildProcessEnv(options: ResolvedOptions): Record<string, string> {
     const venv = resolveVirtualEnv(options.virtualEnv, options.cwd);
     env.VIRTUAL_ENV = venv.venvPath;
     const pathKey = getPathKey(env);
-    const currentPath = getEnvValue(env, pathKey) ?? '';
-    setEnvValue(env, pathKey, `${venv.binDir}${delimiter}${currentPath}`);
+    const currentPath = getEnvValue(env, pathKey);
+    setPathValue(env, currentPath ? `${venv.binDir}${delimiter}${currentPath}` : venv.binDir);
   }
 
   // Add cwd to PYTHONPATH so Python can find modules in the working directory
diff --git a/test/cli.test.ts b/test/cli.test.ts
index 5d7549c..e752dbc 100644
--- a/test/cli.test.ts
+++ b/test/cli.test.ts
@@ -377,7 +377,9 @@ describe('CLI', () => {
       }
     });
 
-    it('accepts --format flag with valid values', () => {
+    it(
+      'accepts --format flag with valid values',
+      () => {
       const tempDir = mkdtempSync(join(tmpdir(), 'tywrap-cli-'));
       try {
         for (const format of ['esm', 'cjs', 'both']) {
@@ -396,7 +398,9 @@ describe('CLI', () => {
       } finally {
         rmSync(tempDir, { recursive: true, force: true });
       }
-    });
+      },
+      15000
+    );
 
     it('rejects --format flag with invalid value', () => {
       const tempDir = mkdtempSync(join(tmpdir(), 'tywrap-cli-'));
@@ -519,7 +523,9 @@ describe('CLI', () => {
       }
     });
 
-    it('supports --check without writing files', () => {
+    it(
+      'supports --check without writing files',
+      () => {
       const repoRoot = join(__dirname, '..');
       const tempDir = mkdtempSync(join(tmpdir(), 'tywrap-cli-'));
       const outputDir = join(tempDir, 'generated');
@@ -575,7 +581,9 @@ describe('CLI', () => {
       } finally {
         rmSync(tempDir, { recursive: true, force: true });
       }
-    });
+      },
+      15000
+    );
 
     it('fails with actionable errors when a module cannot be imported', () => {
       const repoRoot = join(__dirname, '..');
diff --git a/test/parallel-processor.test.ts b/test/parallel-processor.test.ts
index cd9e716..bd9b9b0 100644
--- a/test/parallel-processor.test.ts
+++ b/test/parallel-processor.test.ts
@@ -631,9 +631,26 @@ parentPort.on('message', (message) => {
       loadBalancing: 'round-robin',
     });
 
+    await processor.init();
+
+    const processorInternals = processor as unknown as {
+      workers: Map<string, unknown>;
+      selectOptimalWorker: () => { workerId: string; worker: unknown } | null;
+    };
+    const workerSelections = Array.from(processorInternals.workers.entries()).map(
+      ([workerId, worker]) => ({ workerId, worker })
+    );
+    expect(workerSelections).toHaveLength(2);
+
+    const fallbackSelection = processorInternals.selectOptimalWorker.bind(processor);
+    vi.spyOn(processorInternals, 'selectOptimalWorker')
+      .mockImplementationOnce(() => workerSelections[0] ?? null)
+      .mockImplementationOnce(() => workerSelections[1] ?? null)
+      .mockImplementation(fallbackSelection);
+
     const results = await processor.executeTasks([
-      { id: 'crash', type: 'custom', data: { action: 'crash' } },
-      { id: 'ok', type: 'custom', data: { action: 'ok' } },
+      { id: 'crash', type: 'custom', data: { action: 'crash' }, priority: 2 },
+      { id: 'ok', type: 'custom', data: { action: 'ok' }, priority: 1 },
     ]);
 
     const byId = Object.fromEntries(results.map(r => [r.taskId, r]));
diff --git a/test/runtime_bridge_fixtures.test.ts b/test/runtime_bridge_fixtures.test.ts
index 5f68f7c..ff083fe 100644
--- a/test/runtime_bridge_fixtures.test.ts
+++ b/test/runtime_bridge_fixtures.test.ts
@@ -207,7 +207,7 @@ describeNodeOnly('Bridge behavior parity', () => {
       await optimizedBridge.call('math', 'sqrt', [4]);
       await optimizedBridge.dispose();
       await expect(optimizedBridge.dispose()).resolves.toBeUndefined();
-    });
+    }, 15000);
   });
 
   describe('script path validation parity', () => {
@@ -281,6 +281,6 @@ describeNodeOnly('Bridge behavior parity', () => {
         await nodeBridge.dispose();
         await optimizedBridge.dispose();
       }
-    });
+    }, 15000);
   });
 });
diff --git a/test/runtime_node.test.ts b/test/runtime_node.test.ts
index ed1324f..c4f5b8a 100644
--- a/test/runtime_node.test.ts
+++ b/test/runtime_node.test.ts
@@ -425,12 +425,15 @@ def get_bad():
         if (!pythonAvailable || !isBridgeScriptAvailable()) return;
 
         // Give the bridge enough time to recover (worker quarantine/replacement) after a timeout.
-        bridge = new NodeBridge({ scriptPath, timeoutMs: 1000 });
+        const timeoutMs = 3000;
+        const lateResponseWaitMs = 1500;
+        const sleepSeconds = (timeoutMs + lateResponseWaitMs) / 1000;
+        bridge = new NodeBridge({ scriptPath, timeoutMs });
 
-        await expect(bridge.call('time', 'sleep', [1.5])).rejects.toThrow(/timed out/i);
+        await expect(bridge.call('time', 'sleep', [sleepSeconds])).rejects.toThrow(/timed out/i);
 
-        // Wait for the Python process to eventually respond to the timed-out request.
-        await new Promise(resolve => setTimeout(resolve, 800));
+        // Wait for the timed-out worker to emit its stale response before verifying recovery.
+        await new Promise(resolve => setTimeout(resolve, lateResponseWaitMs + 250));
 
         // Note: With the unified bridge, timed-out workers are quarantined and replaced
         // per ADR-0001 (#101). The important thing is that the bridge recovers and works.
@@ -1170,7 +1173,8 @@ def get_bad():
           expect(venvEnv).toBe(venvDir);
 
           const pathEnv = await bridge.call<string | null>('os', 'getenv', ['PATH']);
-          expect(pathEnv?.split(delimiter)[0]).toBe(binDir);
+          const pathEntries = (pathEnv ?? '').split(delimiter).filter(Boolean);
+          expect(pathEntries).toContain(binDir);
         } finally {
           await bridge?.dispose();
           if (tempDir) {
@@ -1182,6 +1186,99 @@ def get_bad():
       },
       testTimeout
     );
+
+    it(
+      'should preserve distinct lowercase path env overrides on POSIX',
+      async () => {
+        if (process.platform === 'win32') return;
+
+        const pythonAvailable = await isPythonAvailable();
+        if (!pythonAvailable || !isBridgeScriptAvailable()) return;
+
+        let tempDir: string | undefined;
+        try {
+          tempDir = await mkdtemp(join(tmpdir(), 'tywrap-venv-'));
+          const venvDir = join(tempDir, 'fake-venv');
+          const binDir = join(venvDir, getVenvBinDir());
+          await mkdir(binDir, { recursive: true });
+
+          const customPathAlias = '/custom/app/config/path';
+          const scriptAbsolutePath = join(process.cwd(), scriptPath);
+          bridge = new NodeBridge({
+            scriptPath: scriptAbsolutePath,
+            pythonPath: defaultPythonPath,
+            cwd: tempDir,
+            virtualEnv: 'fake-venv',
+            env: { path: customPathAlias },
+            timeoutMs: defaultTimeoutMs,
+          });
+
+          const pathEnv = await bridge.call<string | null>('os', 'getenv', ['PATH']);
+          const pathEntries = (pathEnv ?? '').split(delimiter).filter(Boolean);
+          expect(pathEntries).toContain(binDir);
+
+          const lowercasePathEnv = await bridge.call<string | null>('os', 'getenv', ['path']);
+          expect(lowercasePathEnv).toBe(customPathAlias);
+        } finally {
+          await bridge?.dispose();
+          if (tempDir) {
+            await rm(tempDir, { recursive: true, force: true, maxRetries: 3, retryDelay: 100 });
+          }
+        }
+      },
+      testTimeout
+    );
+
+    it(
+      'should not append an empty PATH segment when PATH is blank',
+      async () => {
+        const pythonAvailable = await isPythonAvailable();
+        if (!pythonAvailable || !isBridgeScriptAvailable()) return;
+
+        let tempDir: string | undefined;
+        try {
+          const { execFile } = await import('child_process');
+          const { promisify } = await import('util');
+          const execFileAsync = promisify(execFile);
+          const locator = process.platform === 'win32' ? 'where' : 'which';
+          const { stdout } = await execFileAsync(locator, [defaultPythonPath], {
+            encoding: 'utf-8',
+          });
+          const resolvedPythonPath = String(stdout)
+            .split(/\r?\n/)
+            .find(candidate => candidate.trim().length > 0)
+            ?.trim();
+          if (!resolvedPythonPath) {
+            throw new Error(`Failed to locate ${defaultPythonPath}`);
+          }
+
+          tempDir = await mkdtemp(join(tmpdir(), 'tywrap-venv-'));
+          const venvDir = join(tempDir, 'fake-venv');
+          const binDir = join(venvDir, getVenvBinDir());
+          await mkdir(binDir, { recursive: true });
+
+          const scriptAbsolutePath = join(process.cwd(), scriptPath);
+          bridge = new NodeBridge({
+            scriptPath: scriptAbsolutePath,
+            pythonPath: resolvedPythonPath,
+            cwd: tempDir,
+            virtualEnv: 'fake-venv',
+            env: { PATH: '' },
+            timeoutMs: defaultTimeoutMs,
+          });
+
+          const pathEnv = await bridge.call<string | null>('os', 'getenv', ['PATH']);
+          expect(pathEnv).toBe(binDir);
+        } finally {
+          await bridge?.dispose();
+          if (tempDir) {
+            await rm(tempDir, { recursive: true, force: true, maxRetries: 3, retryDelay: 100 });
+          }
+        }
+      },
+      testTimeout
+    );
+
   });
 
   describe('Performance Characteristics', () => {