Hello,
This occurs on n two different computer running Big Sur and BTT 3.579. It doesn't do it on Catalina and BTT 3.579.
I often have to enter a password into the terminal when ssh-ing to servers. I have a shortcut (Cmd-P) to Insert/Type/Paste Custom Text and is assigned to Terminal.
After the Big Sur upgrade, using that shortcut brings up the print dialogue on the initial attempt about 80% of the time and pastes about 20%. When I get the print dialogue, I have to hit ESC once or twice and then Cmd-P, repeating this until it works. Usually it takes 2-3 escapes but sometimes more.
Your support is appreciated.