Hi. A couple of comments, Itch never sends notifications when a game is deindexed or reindexed. It's not something they haven't notified you about, it's just that they never do it.
Except for the admin, no one knows how the algorithm that deindexes games works, so we're just speculating, but every time you update your page, there's a chance the algorithm will deindex your game and put it on hold for manual review.
From what you're saying, this seems to be your case. One of your updates was flagged by the automatic algorithm, and no one on staff has been able to review it yet.
I doubt the staff manually reviewed your game and deemed it NSFW. When that happens, the first thing they do is mark the game as NSFW, I'm check your game and appears as SFW. So it doesn't look like any human has reviewed it.