Edit. 2022-09-18
Please try v2.3.0
Hope this solves your problem.

Edit. 2022-09-11
I'm sorry, I don't know why you have a problem. I have tried the video link you sent. it's no problem You can check what I tested from this link.
https://www.youtube.com/watch?v=f_ZOGVqqx9c

I think the problem is that it doesn't remember the last position, maybe because your browser is not using the latest version or some other addon has an effect.

Try uninstalling the addon and close the browser first, then relaunch and install the addon.

Or try installing the addon in Firefox Nightly or Firefox Developer Edition.
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Edit. 2022-09-10
Can you send me a link of the video where the subtitles genereate is on the left side, 2-3 links, I'll try to find a solution.
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I have checked It still works properly.
Please try reinstalling and activating "Remember the last position" again in add-on preferences.