diff --git a/src/metadata/utils/getStart.ts b/src/metadata/utils/getStart.ts
index 9ed6236..09faa49 100644
--- a/src/metadata/utils/getStart.ts
+++ b/src/metadata/utils/getStart.ts
@@ -14,6 +14,6 @@ export const getStart = (testInvocation: TestInvocationMetadata) => {
   if (typeof start1 === 'number') {
     return typeof start2 === 'number' ? Math.min(start1, start2) : start1;
   } else {
-    return typeof start2 === 'number' ? start2 : Number.NaN;
+    return typeof start2 === 'number' ? start2 : undefined;
   }
 };
diff --git a/src/metadata/utils/getStop.ts b/src/metadata/utils/getStop.ts
index 518a9a1..de4e54e 100644
--- a/src/metadata/utils/getStop.ts
+++ b/src/metadata/utils/getStop.ts
@@ -15,6 +15,6 @@ export const getStop = (testInvocation: TestInvocationMetadata) => {
   if (typeof stop1 === 'number') {
     return typeof stop2 === 'number' ? Math.max(stop1, stop2) : stop1;
   } else {
-    return typeof stop2 === 'number' ? stop2 : Number.NaN;
+    return typeof stop2 === 'number' ? stop2 : undefined;
   }
 };