I'm not sure. I created it with the nsfw tag from the getgo.
I know that kbin is a bit less mature than Lemmy. Or maybe they both handle nsfw differently? Do you see other posts from Yiffit where this happens?
"Dripping" has an +18 by it, and so does "Relaxing", and "Loona Tease". "Good Girl!" doesn't, or "Take A Seat", "Wolf In Heat", (or "Bunny Girl", but I don't think that one needs it). None of the ones in playpetyiff have it.
Yeah. I'm chalking it up to being an early alpha, and hoping it gets fixed soon. It does basically mean I won't be reporting anything as not marked nsfw in the future until it's taken care of, as it might actually be.