This consumes about 1/4 of the screen each time (not just one prompt at a time). I can't pretend to have any idea why this is happening. Any ideas? I don't even know where to start in regards to debugging this.
EDIT: it's tmux causing it, not Terminal. Killing the current window fixes it for a while, but it crops up again. I was only using git in the current pane, nothing weird or in the background, etc.