Doepfer

Hi
(sorry for the spam-like subject line)
I just received a Dopefer joystick from Thomann. 

It's installed fine and does what it's supposed to do, but I've noticed that the shaft is very 
loose at its base. So much so in fact that it when I let it rest it seems to be at a slightly 
different offset position each time - I can see because the LEDs light up and I have to keep 
tweaking the offset dial to return it to zero.

Can anyone else with a joystick tell me if this is normal, or should I be returning mine for a 
replacement.

Thanks in advance
Mark