Undo, is confused between wikitext and VE-modes, and misconverts.
I composed a post. I then edited that post, making my last edit in VE-mode.
If I click "undo" at
whilst the sticky-preference is still set for VE-mode, it gives me an incorrect rendering:
If I make another post, and the last edit is in wikitext-mode (to change my sticky preference), and then I click "undo" at the link above, it initially displays as expected:
However, as soon as I click in the text area, to make a further edit, it instantly changes to VE-mode, and mis-renders it again (slightly differently than before):