Thunderbird for Mac just updated to 78.4.0 and all of a sudden the letter y is not showing up in a new email message being typed and the cursor did not move. Thought it was keyboard but it was not the issue. Copied typed text into Text Edit and every time that I had typed y showed up. Then when a new message came in noticed that every y was missing from message and the letter x was replaced by the ("). This also occurred with an email invitation for a Zoom call. Both were from a PC. I've restarted Thunderbird and restarted computer but issue is still there.