Certain keys not working on non-English keyboard layout

[RedAero]

I hope this is the right section of the forum to post this in:

I'm on the latest stable version, 1.3.8.1, x64, running a server in application mode. The server is on Win11, the client on Win10, but I strongly recall this error being present on Win11 as well. The client is using a physical English keyboard, the server is using a Hungarian keyboard, both are set to a Hungarian layout in Windows, and of course both work fine locally.

The error: the letters "ő" and "ű" aren't sent through to the server. All other keys, including non-English ones like "é", "á", "ö", "ü", etc. are sent fine, even ones I have to send via an AltGr combination ("í" and "Í", with J and I respectively). I have tried I think every combination of client and server keyboard settings in UVNC, and one of two things can happen: if I select the Japanese keyboard setting in the client, an "o" and an "u" replace "ő" and "ű", and if I select the International keyboard setting on the server, some weird thai-looking characters are sent. Otherwise, nothing happens when I press these keys (which, on an English keyboard, are the open bracket and backslash keys, respectively).

It gets stranger.
If I set the client to English but leave the server as Hungarian, and press the "[" key on my English keyboard, the server interprets an AltGr+G key combo, the key combo for "[" on a Hungarian keyboard. But because AltGr is translated as Ctrl+Alt, this can cause problems with some programs such as Notepad++, where Ctrl+Alt+G is a mapped key combo in the Compare plugin (something similar happens with the backslash, which is AltGr+Q). Other keys, as far as I can tell, are transmitted correctly, although I'm sure the the AltGr issue is present elsewhere too (e.g. a semicolon is AltGr+Comma).
If I set the server to English but leave the client as Hungarian, the client keyboard behaves as if it's English, except again, the open bracket and backslash keys don't work at all.
If I set both to English... I don't even know what's happening. It seems to apply a keyboard layout I've never encountered - several keys don't do anything, apostrophe becomes an exclamation point, forward slash becomes a caret, equals becomes an ampersand, and so on.

I didn't try these combinations with the various UVNC settings because there are way too many combinations, and I didn't dis- or reconnect while changing keyboard layouts.