Thanks for the kind words, Simon! I think you probably just got used to the quirks :-). The worst ones are around pasting, which is mostly IntelliJ complicating things for parinfer by making a lot of whitespace changes in order to format the code, in addition to pasting it. But there's also all these:
https://github.com/cursive-ide/cursive/issues/2945. I'm planning to do a round of parinfer fixes soon though. It's so complicated that I can't hold it in my head for long, so I have to load it into my brain cache and then do a batch of fixes at a time.