Offering skill duration not extended by runegraft of the warp

Runegraft of the warp should slow the expiration rate of Bone offering, flesh offering and spirit offering since they are all buffs

I've tested without and with leash of oblation so that they effect me and neither seem to work.

I also verified that mantra of flames give you flat fire damage for each of these offerings effecting you which should confirm they are definitely considered buffs.