Minibuffer text getting sliced in half

I've got a strange problem where minibuffer text is getting intermittently cut in half horizontally. So for a single-line message of the letter "a", only the bottom half of that letter will appear, like the line height is too large for the minibuffer. Any ideas on what could cause this? It's for all messages, not some specific package, and starts and stops randomly. Using Emacs 29.0.50

Same problem when you run Emacs with `emacs -q`?

It's intermittent, so things display fine on startup with -q and without. It just pops up once or twice a day during use for maybe 30 seconds, then fixes itself.