I've started losing characters in other apps, specifically MS Word 2019 (haven't tried the other MS Office apps). This happens when I am typing a word in a document and letters will be dropped, resulting in a partial word. It's not necessarily the first letter but it seems to be random. When I quit KM, it stopped. That's the only app I have noticed it happening in...e.g. this message has no problems. I only have Brave browser and Mail open, so no other memory hogs.
Any typed string triggers ? You could also look into the macros you have set up to be active specifically under MS Word, if that's the only application you're noticing the problem.
Time to put this to rest. I've been having serious problems with delays and dropped characters in most apps today. I quit KM and the trouble is still here. Going to look in somebody else's yard.