I feel like I'm going crazy, but I live with 2 other people so this shouldn't be a case of "someone did this and we didn't notice". My village has been 90% or higher auth since it was founded because I'm playing actively. I've now seen two instances of decay on my Vclaim.
1) I first noticed a milestone had decayed to 75% that's inside my kitchen. Very weird I thought, maybe my wife or the one other casual I'm playing with partially bashed it for no reason? Whatever.
2) One of my logs decayed into a mirkwood log inside the base. This is only something that happens normally on unclaimed land, I've had logs sit around for 10months IRL before in a base and never seen this, while logs will mirk outside after a couple months.
So I'm not entirely what's going on. it's only these 2 incidents I've seen, it'd almost make more sense if the village was decaying everywhere, but nope. And certainly the mirkwood log wouldn't be a prank, it's in a random area of the base no one goes into. No overlapping Pclaim shenanigans either.