Transcription Fails Silently and Ends with No Dialogue Found

See this thread in the regular forum:
 

Users report transcription failure resulting in “No dialogue found” for files that appear to have dialogue and that work in earlier versions. Some users report this as early as 26.0.0. More users report this coinciding with upgrading to 26.2.2. I have wondered if some of the users with problems are using non-English installations or non-English files. I took special note of ​​@mattchristensen1’s post that raised the question of the large downloads involved in the extensive updates to transcription in 26.2.0.

The user I link to reports that this also occurs in the Beta 26.3.0, build unspecified. I am posting this bug report for him, because I realized that the new forum makes posting a Beta bug report with the system information less straight-forward than previously.

I believe the results reported are not in themselves diagnostic. Transcriptions may fail after starting for multiple reasons, and when they do, they often show no transcription and a No dialogue found message.

Steps to reproduce:
1 Attempt to create a source media or static/sequence transcription by multiple methods.

Result: Transcription process starts, and window closes. There is no transcription. Text panel/Transcription tab shows “No dialogue found.”
Expected: Transcription completes and is available.

For the record, this is my system where transcription works. I have been unable to replicate the problems in PR Releases 26.0.0, 26.0.1, 26.0.2, and 26.2.2 and PR Beta 26.3.0.58 and 26.5.0.3. I have only tested an English .mp4 with a stereo track.

System info
    Application: Premiere Pro (Beta) v26.5.0.3
    OS: Windows v10.0.26200, RAM: 63.80 GB GB, CPUs (logical): 16