Open any Writer file.
^o (ctrl-o) is supposed to open a file —see File>Open. Instead, it opens the Format menu, which ~o (alt-o) should do since the o in Format is underlined. Bug?
Your OS, LO version, other relevant details? Can’t see that with Version: 6.2.2.1 (x64)
Build ID: fcd633fb1bf21b0a99c9acb3ad6e526437947b01
CPU threads: 12; OS: Windows 10.0; UI render: GL; VCL: win;
Locale: ru-RU (ru_RU); UI-Language: en-US
Calc: CL
Rather independent of the software I am using under current Win 10, I sometimes experience strange changes in the keyboard settings not related to anything I did consciously. This may cause e.g. the Ctrl key to act as if it is the Alt key …
My only way to get back full control then is to restart Win.