There are some actions where a vote from moderator has immediate effect (i.e., there is no need for votes from other users). This is the case for closing and reopening posts. However, in these cases if community disagrees with the moderator decision, 5 users can revert this decision (by voting to reopen/close).
As far as I can tell, the situation is different in the case of deletion. If a post is deleted by a moderator, regular users cannot vote to undelete. I have just tested this and got an error message: "A moderator has deleted this post and it cannot be undeleted." Also this answer, mentioning that this feature was implemented, confirms that delete votes by mode behave in this way: Lock posts by default, when deleted by a moderator?
I have no idea what is the situation for posts which were undeleted by a moderator. But I would like make this question a bit more general:
TL;DR: What are actions which can be made both by regular users (with sufficient reputation) and by mods, but when done by moderators they become irreversible?
Are delete votes the only such action?