Yes, I realized that and turned-off Zero RPM option in AMD software, and I heard the fan spining, but the data keep in 0 or in a fixed number.
But finally, I found the issue! Sapphire help desk helped me with that.
The issue is with RGB Fusion 2.0 software. This program, I rly don't know why, mess with fan reading data.
Just uninstalled, restarted pc, and... done.
The only problem is that I don't know how to manage my RGB LEDs now. hahaha.
Any sugestions?