last caption timestamp fix

yttemporal180m.py

@@ -126,7 +126,9 @@ class yttemporal180m(datasets.GeneratorBasedBuilder):
                                 "video_url": url,
                                 "caption": caption,
                                 "timestamp_start": timestamp_start,
-                                "timestamp_stop": timestamp_stop,
+                                "timestamp_stop": timestamp_stop
+                                if el["time"] != last_caption_timestamp
+                                else last_caption_timestamp,
                                 "meta": json.dumps(
                                     metadata_dict, default=json_serializer, indent=2
                                 ),