Sorry I did not respond to your first thread on this topic.
I think you are seeing the Youtube 2-line rolling captions. In the versions before the caption workflow change (PR 2020 and before), PR would import these as 2 line captions, with timecodes that approximated roll-on. They would work, but the sync was not desireable.
In the new caption workflow, in my tests, PR brings every line of caption into ONE caption with a very long timing, and breaks captions only where there is an audio gap that results in no overlapping timecode.
In any event, you can avoid this type of download.
The overlapping timecode download occurs when you use the Youtube "automatic" caption and download from there. In the Studio pages, for that video, select the "details" or edit and look for "subtitles" on the left. One subtitle language/version (often the only line) will have "(Automatic)" next to the language. If you hover over that line, 3 dots will appear at the right end of the line. Left click, then click "Download" and "srt." The resulting srt will have the overlapping timecodes, and will not work correctly in PR 2021 and newer.
Instead, if you already have a non-automatic caption stream n Youtube that you prefer, use that. Or create another one by clicking on "Duplicate and Edit" on the Automatic line. Once there, "Publish" that "draft." It will create another line in the subtitles page.
Pick your preexisting or new, non-automatic subtitle, and click on the 3 dots at the right end, and download srt. This download will have 2 lines per caption, with timings set by Youtube. These will import to PR, creating 2 line captions with grossly accurate, if clunky timecode. (I found the timecode very similar to what PR achieved in the PR2020 version.)
If you want one line captions, you can achieve this by editing the overlapping srt in a third party application. For example, open the srt in Subtitle Edit (free) and use its function for "fix common errors" to retime to single lines. Be sure "fix overlapping times" is checked. And after running the selection, click "apply."