I own the Z70V (not VA), but I think you are describing the issue I'm having now.
After I updated to the newest Z70V BIOS listed on the Asus support site, the GPU fan (left side of the chassis) has been bothering me a bit.
I've been monitoring with Everest/Speedfan, and it seems that as soon as the GPU ("Remote 2") hits 59C, the fan kicks on to about 52% (~2180 RPM). That's good and fine, because personally this isn't too loud for me and it'll help cool my components. However, the fan will never turn off from that point on: even when the temperatures drops to let's say 53C, the fan will stay on at ~2180 RPM.
Now, I actually sent an email to Asus about this, and here is their cryptic response:
Basically ,we have a blanced thermal and acoustic solution in the
BIOS to control fan activity.
Not very helpful.
I've tried manually forcing the GPU fan to run full blast for several minutes, but I haven't been able to get a low enough temperature to cut off the fan (that is, if such a cutoff temperature even exists).
My only wish now is to find a way to manually set the threshold temperatures if somebody is able to figure out how to do it.
FYI, because I'm undervolting, my CPU fan rarely comes on. Even on the event that it start spinning, the fan will properly stop once the CPU has been cooled sufficiently.