This happens to me only with some videos, but when the automatic subtitle transcription ends, it is frozen in "transcribing on device" and does not create the subtitles, it just remains with the bar filled.
Previously I had used it with the same video files (same frame rate and same resolution) and it worked fine, but now it won't let me.
We're sorry about the poor experience. Let us know the version of Premiere Pro that you are using. What is the length/duration of the clip/sequence that you are transcribing? Also, is it always getting stuck in the end? We're here to help, just need more info.