Ron was on the right track, but not quite the right reason 🙂
It was a theme issue, only in the ‘kiwitrees’ theme. A while back I added some css styling to stop buttons shrinking too small where their label was perhaps only a couple of characters long, i.e. “min-width: 100px;”.
Trouble is I targetted it to the tag “button”, and other things, like google maps, also use the same tag!
So the fix is very easy:
In kiwitrees/themes/kiwitrees/style.css, change line 136