I feel it's unnecessary for multiple flags to be active on a post at the same time. As far as I know, multiple flags do nothing to affect a post when they're active at the same time. I've been noticing this a bit lately: it's like people see a flagged post and bet on it being bad enough to get deleted, so they flag it too. Why? To up the number of successful flags on their account details? A misunderstanding of how the system works, looking to "cast their vote?"
Feel free to debate this, but it's been my understanding that appeals should only be used on posts that are currently deleted. Users tend to use the appeals system to start a debate or flag/appeal war at the top of a flagged post instead of in the comments, and this feels like an unintended result of the system. If users are meant to vote on whether a post should be approved, it should be counted separately like approvers' opinions on pending posts currently are, but that's a whole different issue. In relation to the first paragraph, multiple appeals on a post don't do anything extra for the post as it's already on the moderation appeals page (I haven't specifically checked, but I don't think multiple appeals "bump" it up the list) except perhaps to again cast a vote in a non-election.
It's a small issue, but I think it'd make the system feel more solid and clear on its actual workings if, when a post is either currently flagged or currently appealed with either situation unresolved, the option to do so is either removed or gives an error claiming the post is already in "limbo." If a flagged post is approved then the flag option should return as it functions now and if it's deleted the option to appeal should become available. This, however, does somewhat conflict with appealed posts currently never being "resolved" unless they're undeleted (we still have "active" appeals 5 years old); perhaps appealed posts should swap their status to "resolved" (but still deleted) after a set time similar to how pending posts switch to deleted. Maybe after a week or even a month. Having 139 pages of appeals is wonky.
I was originally just going to plonk this in a Github issue, but it does feel like something worth gathering opinions on.