Why is one fan spinning at one third the speed of what it's supposed to?

I have a FT02 case hooked up to a Scythe Kaze Master fan controller.

It has three 180mm fans (AP-181s).

One of the 180mm fans spins at a max 690RPM. The other two 1200RPM.

Why is one fan refusing to spin faster?

i would return the one fan that isnt spinning the right speed, or try swapping around the connectors

are you adjusting the controller at the same position for all fans?