I have seen plenty of partially buried TP that looked a lot like it was dug up. I have seen marmots dig in any area they smell pee.

A worse problem is Kleenex left by the side of the trail. It is not brown with poo, but Kleenex degrades much less than TP. The use of Kleenex is even less essential than TP. Learn to do the one-nostril snot blow-out.

Whether it degrades in one season of twenty, matters not. You still see the ugly stuff until it is degraded.