[CLIENT] Chat bug since 4.21

Since patch 4.21, I have encountered a weird bug in the in-game chat. When I want to type in chat, it randomly inserts "^" signs after every other key press or so, as if I was constantly hitting the key, rendering my messages obnoxious at best and illegible at worst. I think I know where it comes from - as I have a European QWERTZ keyboard, this key is to the left of the numbers row and thus I have bound my trinket to it, as it is an accessible key. I have been doing this for a long time, and never had any problems with it. However, since patch 4.20, the issue above occurs. My guess is that something changed for that patch and now the client somehow logs all the "^" key presses and starts inserting them as soon as I start to type. This issue is in-game client specific, it does not affect the launcher or any other program, aside from the fact that when I tab out of the game and type text into any other program, the first letter or sign might be "^", but not more than that. The issue sometimes, but rarely, stops mid-game, and can then start again. This is not reproducible, as I have found no possibility to shut it off. It just sometimes stops after no particular event (I keep using the trinket with that key, etc.). I guess I just could find another key binding for my trinket, but this has worked very well for me since the introduction of trinkets, and I would love to be able to continue using it. I realise that this issue is very specific to me, at least on NA, since I have a European keyboard, but I would guess that the same would happen to me on the EUW client. Any insight on this would be much appreciated.

Yours sincerely, Hollow Bear