I just skimmed the thread but I can provide some info.
The ‘forcing originals’ option was working quite well about a year ago.
Then there was a netflix change in how they distributed the subtitles that forced me (I thought) to push the netflix player (using my bag of tricks) towards always setting the track we would use for the translation language, even when LR was ‘off’, which was unfortunate for some ppl, but, I thought necessary so that LR would have the necessary translation track available.
Recently I realised that I could do this only when LR is enabled, and should still work okay. This change, for some reason, resulted in the ‘force originals’ option misbehaving… not sure why. The code around setting subtitles is a little touchey, you have to ask netflix to change track nicely then wait around until it does change, while other things are going on… anyways.
tldr: will get this sorted out when I have a clear mind to put to the task, hopefully soon. 