Air Venturi Avenger issue

So I took my .22 Avenger out for a drive on Friday. Shot great as usual. Consistentoy smacked the 4” spinner at 100yds. With both 14.3 And 19gr Crosmans. Love this rifle.
Fast forward to today. Fresh fill to 4kpsi. Just under full pressure. Ran Two shots and the pellets became very stiff to load. Two more shots and the cocking handle just came to an abrupt stop just as the prob entered the chamber. Will not load a pellet. Works nice and smooth otherwise, but is a solid stop at that point. So we shot the other guns all morning. The Cayden is still awesome.
When I returned home I degassed the Avenger for tear down so that I could see what the heck happened to my gun. As soon as I degassed it , the cocking lever closed right up. So I recharged the gun and ran a mag through it. No issues.
Anyone have an idea what the problem could have been? I’m stumped.