Manual fan speed - HiveOS making its own mind up

I’ve 8 580’s running in my rig and as its summer its getting hot. Autofan is off (because imo its crap and does what it wants when it wants).

I manually set a GPU fan speed to 80% to help it cool, from the previous setting of 60%. I then set another GPU fan speed to 80% and the one I just changed reverted to its previous setting of 60%. I go back change it to 80% and the one I’ve just changed goes back to 60%. Repeat.

Its the first time I’ve ever seen this bizarre behaviour. Anyone else?