Could definitely be normal depending on the temp your gpu is idling at.

When switching the vbios did you reboot the computer and use gpu-z to see if both vbios show a different version?

Let me know if both show a different version.

Shutting down your PC instead of restarting after switching the VBIOS might be an issue if Windows "Fast Startup" is on..You can turn it off and see.

I think that with no software (Precision/Afterburner) running/intervening and the VBIOS switch in the Normal position, the GPU fan (left) should run only when GPU temp reaches 60C+ and be off below 60C..The Power and Memory fans should only run when their temps reach 60C and be off below 60C no matter the VBIOS switch position. 

ACX 2.0/ACX 3.0 have fan on/off temps of 65C but I think they changed that to 60C with the iCX cards like yours.

If you have questions about it you can always Contact EVGA Customer Service..They can provide you with a Normal and/or OC VBIOS.exe if necessary.

Its normal!
 
I have the same card, and can confirm that the 3rd fan (closest to the back of PC) consistently runs at 20% in OC Bios. However in the Normal Bios it will shut all the fans off if below a certain temperature. You can download MSI afterburner, to see that the factory fan curve settings.
 
I've always left mine in the OC bios, still idles at 35C and never gets above 60C under full load. EVGA's cooler design is excellent on this card.