Flaying immunity

[nilsbloodaxe]

Just a quick question to those out there who have a bit more knowledge about the underlying mechanics than I do. I was playing the Imp experimental branch the other day, and I found myself with the Flay status, despite Imps being torment immune. I don't ever recall having a Gh, Mu, bloodless Vp, or even a Gr get the Flay status, so I thought it was tied to torment immunity or resistance, but clearly this isn't the case. What exactly makes one immune to flaying?

[Cheibrodos]

holiness strikes again