I use the SIL IPA keyboard frequently filling out webpages in my browser. While it works well, there has been a bug for some time. Most diacritics will work but using onewill erase the glyph before.
Ex: to type a breve over a character, I would normally type “***”. The first one will erase the letter immediately before, the second and third will erase the two letters before that. Adding two spaces after the character and then typing the sequence for the diacritic will normally place it above the character.
This is a consistent issue in Firefox, Chrome, and MS Edge-Chromium.
The work around isn’t working in Chromium-based browsers. It will type stacked versions of the diacritic.