diff --git a/youtube_dl/extractor/peertube.py b/youtube_dl/extractor/peertube.py
index cc4c8bd5c..d7f48b646 100644
--- a/youtube_dl/extractor/peertube.py
+++ b/youtube_dl/extractor/peertube.py
@@ -498,14 +498,11 @@ class PeerTubeIE(InfoExtractor):
             caption_path = str_or_none(entry.get('captionPath'))
             if language_id and caption_path:
                 caption_url = 'https://%s%s' % (host, caption_path)
-                if language_id in subtitles:
-                    subtitles[language_id].append({
+                caption_dict = {
                         'url': caption_url
-                    })
-                else:
-                    subtitles[language_id] = [{
-                        'url': caption_url
-                    }]
+                    }
+                if subtitles.setdefault(language_id, [caption_dict]) != [caption_dict]:
+                    subtitles[language_id].append(caption_dict)
         return subtitles
 
     def _real_extract(self, url):