diff --git a/.github/workflows/e2e-tests.yml b/.github/workflows/e2e-tests.yml
index 4237d3f41ba..9bec57d2607 100644
--- a/.github/workflows/e2e-tests.yml
+++ b/.github/workflows/e2e-tests.yml
@@ -436,6 +436,21 @@ jobs:
               cd e2e/bug-14036
               composer install
               ../../bin/phpstan analyze
+          - script: |
+              cd e2e/vvv-with-debug
+              OUTPUT=$(../../bin/phpstan analyze -l 0 -vvv --debug test.php 2>&1)
+              echo "$OUTPUT"
+              ../bashunit -a not_contains 'Parallel processing scheduler' "$OUTPUT"
+          - script: |
+              cd e2e/vvv-with-debug
+              OUTPUT=$(../../bin/phpstan analyze -l 0 -vvv --debug --configuration parallel.neon test.php 2>&1)
+              echo "$OUTPUT"
+              ../bashunit -a not_contains 'Parallel processing scheduler' "$OUTPUT"
+          - script: |
+              cd e2e/vvv-with-debug
+              OUTPUT=$(../../bin/phpstan analyze -l 0 -vvv test.php 2>&1)
+              echo "$OUTPUT"
+              ../bashunit -a contains 'Parallel processing scheduler' "$OUTPUT"
 
     steps:
       - name: Harden the runner (Audit all outbound calls)
diff --git a/e2e/vvv-with-debug/parallel.neon b/e2e/vvv-with-debug/parallel.neon
new file mode 100644
index 00000000000..39a1d6edcd7
--- /dev/null
+++ b/e2e/vvv-with-debug/parallel.neon
@@ -0,0 +1,3 @@
+parameters:
+    parallel:
+        maximumNumberOfProcesses: 2
diff --git a/e2e/vvv-with-debug/test.php b/e2e/vvv-with-debug/test.php
new file mode 100644
index 00000000000..b3d9bbc7f37
--- /dev/null
+++ b/e2e/vvv-with-debug/test.php
@@ -0,0 +1 @@
+<?php
diff --git a/src/Command/AnalyserRunner.php b/src/Command/AnalyserRunner.php
index c452ba4976d..1da03e53ed3 100644
--- a/src/Command/AnalyserRunner.php
+++ b/src/Command/AnalyserRunner.php
@@ -71,30 +71,27 @@ public function runAnalyser(
 			);
 		}
 
-		$schedule = $this->scheduler->scheduleWork($this->cpuCoreCounter->getNumberOfCpuCores(), $files);
-		$mainScript = null;
-		if (isset($_SERVER['argv'][0]) && is_file($_SERVER['argv'][0])) {
-			$mainScript = $_SERVER['argv'][0];
-		}
+		if (!$debug && $allowParallel && function_exists('proc_open')) {
+			$schedule = $this->scheduler->scheduleWork($this->cpuCoreCounter->getNumberOfCpuCores(), $files);
+
+			$mainScript = null;
+			if (isset($_SERVER['argv'][0]) && is_file($_SERVER['argv'][0])) {
+				$mainScript = $_SERVER['argv'][0];
+			}
 
-		if (
-			!$debug
-			&& $allowParallel
-			&& function_exists('proc_open')
-			&& $mainScript !== null
-			&& $schedule->getNumberOfProcesses() > 0
-		) {
-			$loop = new StreamSelectLoop();
-			$result = null;
-			$promise = $this->parallelAnalyser->analyse($loop, $schedule, $mainScript, $postFileCallback, $projectConfigFile, $tmpFile, $insteadOfFile, $input, null);
-			$promise->then(static function (AnalyserResult $tmp) use (&$result): void {
-				$result = $tmp;
-			});
-			$loop->run();
-			if ($result === null) {
-				throw new ShouldNotHappenException();
+			if ($mainScript !== null && $schedule->getNumberOfProcesses() > 0) {
+				$loop = new StreamSelectLoop();
+				$result = null;
+				$promise = $this->parallelAnalyser->analyse($loop, $schedule, $mainScript, $postFileCallback, $projectConfigFile, $tmpFile, $insteadOfFile, $input, null);
+				$promise->then(static function (AnalyserResult $tmp) use (&$result): void {
+					$result = $tmp;
+				});
+				$loop->run();
+				if ($result === null) {
+					throw new ShouldNotHappenException();
+				}
+				return $result;
 			}
-			return $result;
 		}
 
 		return $this->analyser->analyse(