Cut and paste not working, Ctrl-H missing in Writer

Since upgrading to Ubuntu 20.04 cut and paste doesn’t work. When I paste I get the text from the last time I used it. I can get the correct text by cutting and pasting twice, but obviously that isn’t workable.

The loss of this very basic function has made Writer almost unusable.

Version: 6.4.2.2
Build ID: 1:6.4.2-0ubuntu3
Ubuntu 20.04

Both things work as intended in openSUSE Leap 15.1, so maybe it’s an ubuntu/mutter problem. See for example this answer.

I’ve only done a very quick check, but replacing Mutter with Wayland seems to work.