I just wanted to say thank you for bringing this up. My fans had the same issue on my Crosshair VI, randomly (and often) either getting stuck on full-power or turning off completely. This thread led me to uninstall Aida and everything has been running perfectly since then.
I am upset I can't run Aida on my main computer anymore, but I know the pre-set temperatures are being maintained properly and my fans are running correctly. I sure hope this annoying issue can be resolved, but it looks like it may be something that will be around for a while.