Upgrade from NC 31 to 32: Board shares got deleted #7762
Description
When we updated our Nextcloud instances from NC 31.0.14 to 32.0.6 last week, a bunch of board shares went missing.
Reproducing it, the shares are removed from the oc_deck_board_acl table on the first cronjob run after the upgrade, and it seems to involve only boards that are shared with circles that have circles as members themselves (yes, that is possible apparently).
It doesn't seem like the DeletedCircleCleanup migration is at fault, as there's no "Removed circle with id" messages in the logs.