Werd Sr boost Problems

[harangatang]

So.. I searched, but I didnt really see anything close to this so

Ok, on stock boost, ~7-8 psi, its fine all day. Hits 8psi, whatever
If I turn it up to ~10-11, it will hit full boost once then it won't go over like 1-2 psi. If I turn the car off, leave the boost controller alone, turn it back on, it will hit 10-11 psi once, then not go over 1-2psi again.. Even at 3/4 throttle.
If I turn it back down to 7-8psi, its fine all day..

So, I really have no idea what the cause of this could be.. bad boost controller (I have a HKS manual), bad wastegate, electronic issues...

Help me out guys!