Internal key state tracking breaks character entry through ALT codes, e.g. ALT+0-2-4-1 outputs `ñ`
I commented out cpyHook.i line 104 "UpdateKeyState(kbd->vkCode, wParam);" (thankfully not affecting PyHK's state tracking, which I'm using) and ALT codes started working.
I have yet been unable to determine how this functionality impacts the ALT code key state so that it doesn't work.