Playback speed slows down when repeated

The playback speed of the video slows down when I repeat a subtitle. It incrementally slows down more each time I click the ‘S’ key to repeat. The video is:

I am in the United States, and am learning French so I’m using the subtitles in French.

There is no playback-speed control in LR. The Youtube playback speed shows “Custom(1)”.
A workaround is to change the Youtube speed to something other than Normal, then change it again back to Normal. But the problem comes back quickly.

A similar problem was reported over two years ago, without any responses to it:

I wish to report that the cause of this issue was “user error”. I had another plugin installed, “Video Speed Controller” that used the same hot-keys as LR. Its decrease-speed key was captured first and this caused the incremental slow-down.

I hope my reporting will at least help others to be aware that using mulitple plugins can effect one’s performance and outcomes.