bear hide slipping

[Muthagoose]

Unless you are seeing residue from any infestation I would suspect one of 2 things
First could be from the outfitter or hunter--the hide wasnt properly and timely fleshed.Heat and the lack of salt is huge in this stage. I keep a freezer at camp just for hides and dont roll them up till they are chilled.Then hydro flesh them..
2nd it may be from the taxidermist.Lax in care of handleing or tanning,poor fleshing job,to high of PH level.
Do these mounts have a greasy feel to the slipped areas?Are you seeing residueIE bug's droppings? Is there a smell to the mounts?