After enabling, you must force an disk scanning from System-->Tasks. Unless I'm wrong, subtitles file naming happens before the mods are run so the hi extension will remain.

Thanks for your (very) quick reply!

After some more testing I believe I got the desired behavior after enabling the "Use HI subtitles as a fallback" setting for the Embedded Subtitles provider and leaving "Use Embedded Subtitles" under "Performance / Optimization" disabled. Embedded HI subtitles now give a 100% score and the "Hearing Impaired" option under "Post-Processing" ensures all HI tags are removed so I end up with a high quality, clean and in-sync subtitle! :)

However, now, as I'm finishing up my tests all of a sudden the embedded provider is not working anymore and I'm getting lower grade subtitles from my other providers.

Looking under System-->Providers I see that the Embedded Subtitles provider is disabled because it encountered an error and has status "FileNotFoundError". This seems like an issue to me. If it encounters an error on one movie or episode it won't extract the embedded subtitles on all other movies/episodes for the next 10(?) minutes. Maybe this provider shouldn't be disabled automatically.

But even after the status returned to "Good" again Bazarr still wasn't automatically extracting the embedded subtitles, not even an hour later when pressing the "Scan Disk" and "Search" buttons for that movie, which I retried several times. I had to restart Bazarr and after that it would immediately extract the embedded subtitle when pressing "Search".

Any idea what might be going on here? I'm afraid that Bazarr won't extract any embedded subtitles after it encounters a single error with that provider, and it might be weeks before I restart Bazarr and the during which I won't notice the issue at all.