Some podcasts insert personalized ads (the technnical term for this is "dynamic ad insertion") depending on your location and other data. When you listen to an episode, it is possible that your ads were different from the ads served to our transcription server. When this happens, the transcripts can go out of sync with the audio. We detect the mismatch and show a warning.
We're working on solving this issue and making sure that the audio and the transcript are always in sync.