@Julian: I’d argue that if a simple accidental click somewhere can cause this, that’s a loaded gun pointed at the user’s toe, and hence a bug in the installer.

@Brian: I’ll try the 22.04 images. I’ve kept trying with 20.04.5, but have yet to find another instance of this occurring, so it’s obviously not easy to trigger.

I’m not particularly troubled by this issue (and the original reporter doesn’t seem to be either), so feel free to adjust ’Importance’ accordingly.