diff --git a/src/test/dispatcher.ts b/src/test/dispatcher.ts
index 35b4d6fe08..7d59a987b8 100644
--- a/src/test/dispatcher.ts
+++ b/src/test/dispatcher.ts
@@ -253,7 +253,11 @@ export class Dispatcher {
     });
     worker.on('stepEnd', (params: StepEndPayload) => {
       const { test, result, steps } = this._testById.get(params.testId)!;
-      const step = steps.get(params.stepId)!;
+      const step = steps.get(params.stepId);
+      if (!step) {
+        this._reporter.onStdErr?.('Internal error: step end without step begin: ' + params.stepId, test, result);
+        return;
+      }
       step.duration = params.wallTime - step.startTime.getTime();
       if (params.error)
         step.error = params.error;
diff --git a/src/test/workerRunner.ts b/src/test/workerRunner.ts
index 68e65b6ba0..4108fa3a00 100644
--- a/src/test/workerRunner.ts
+++ b/src/test/workerRunner.ts
@@ -273,7 +273,7 @@ export class WorkerRunner extends EventEmitter {
       },
       _testFinished: new Promise(f => testFinishedCallback = f),
       _addStep: (category: string, title: string) => {
-        const stepId = `${category}@${++lastStepId}`;
+        const stepId = `${category}@${title}@${++lastStepId}`;
         const payload: StepBeginPayload = {
           testId,
           stepId,