Cursor not working properly in TextEdit, moves on its own

I set up a brand new Macbook Pro M2 to use Lockdown mode, and first thing I did was use TextEdit to write. The cursor is behaving strangely - as I'm typing, it goes back several steps on its own even when I'm not touching the trackpad or keyboard. There's no external mouse or trackpad or keyboard connected. If I hit the right arrow key a few times to get the cursor to the end of the word, it won't budge. It stays several letters before the end. Has anyone every heard of this and how do I fix it?