Steps to reproduce:

1. Create a comandline that exceeds the terminal height:

bind \cg 'commandline -i "echo \'" (seq 1 $LINES)/$LINES "\'"'

2. Hit Control+G

3. Observe that fish fails to draw the last line

4. Type something. The cursor moves but no characters are echoed.

Scrolling up to the prompt I see that fish has started drawing the commandline at the wrong location, resulting in this screen.

$ echo '
  1/59


  2/59
  3/59

Happens at least on 3.1.2 and current master.