I think I’ve (accidentally) found a reliable way to reproduce this:
- Have a card with a checklist
- From the card’s hamburger menu, select
Delete, but don’t touch the (”Delete card?”) confirmation prompt!
- With the card deletion confirmation prompt still visible, delete the checklist (choose
Deletefrom the checklist title, then confirm the checklist deletion)
- Now select
Deletefrom the (still lingering) card deletion prompt
Boom! The card (and the board) is now undeletable.