I've asked, Vitor says its not his bug, its upstream in the default keyboard.
Installing a different keyboard fixes it, haven't found anything else that helps... :(
Discussion
OK. I've never seen it manifest in any other app, but I'll try swapping kybds. Thx.
That seems unlikely given I've used dozens of apps and ONLY get the issue in Amethyst. At minimum, I feel like there has to be some sort of weird interaction between the two.
It may not be a bug by strict, technical definition, but it appears to be an annoyance quite specific to #amethyst + default #Android keyboard. I switched to #futokeyboard and the behavior stopped
I'd definitely count it as a bug. Maybe I'm thinking about it wrong, but I see two options.
One, #Amethyst handles text input the same as at least some popular apps I've used, in which case the keyboard should process it the same as in the other cases, so the bug is from the keyboard and should appear in other apps. This doesn't happen in my experience, and the #Android keyboard has probably been around in some form or another for 15 years, so it seems odd for this just to crop up here and now. Not impossible, but seems unlikely.
Two, Amethyst handles text input slightly differently than other apps, so the keyboard isn't receiving information properly, or at least not in the expected format. Given the keyboard is used in thousands of other apps without issue and that in my case, the preceding space or punctuation is removed while still deleting characters, not when actually inserting a spell checked word from the keyboard, it seems like the error is a lot more likely to be in Amethyst. Not impossible for it to be the keyboard still, but it's so uniquely Amethyst, it's hard to imagine how.