Does the Osprey you are using have the piston or the fixed barrel spacer in it. For it to cycle reliably it should have the piston in it.
Silencerco - Osprey - Accessories
What is the recoil assembly you are mentioning.
SilencerCo ships, and most dealers stock, the Ospreys with a 1/2 x 28 piston (Nielsen Device), unless you request a different thread through the dealer. To use the fixed barrel spacer you remove the spring from the piston, slide the FBS over it and reinstall. By desing, the FBS cannot be used without the piston installed. So if bearhawk was using the FBS, he should definately know it because he would have had to be the one to buy it seperately and install it. Just wanted to clear that up first.
I would go down the road BigBoss is sending you first. Check the obvious. I really have never had a need to change the recoil assembly on any modern tilt barrel semi-auto I have owned, to get it to function with a suppressor (assuming it has a booster). My P30 w/ threaded L barrel runs fine with my Osprey. Case in point... I have a pre 2004 Walther P99 (prior to being Americanized). I bought a factory SD barrel and SD recoil assembly from Earl's Repair Service. The recoil assembly that ships from the factory has a black 50 newton spring. For functionality, Earl recommended using the red 48 newton assembly with a suppressor. So I bought it also. What I can tell you is the P99 fuctionns flawlessly with either of them.
If we were talking about a .22 or an unlocked / straight blowback design, I would say recoil spring. However IMHO, I would take the paths of least resistance and $$$ first. Good luck... Hopefully someone suppressing a USP 9 can offer some advice also.
