With the gas block turned all the way closed, the gun should not cycle. At a minimum, it should short stroke.
Is it possible that the gas adjustment screw is locked in place and the clicks you feel are actually the hex inside the adjustment screw being rounded off? There is a set screw on the side of the gas block for adjusting the detente. If it is set too deep, the gas screw will not rotate. Another set screw is located on the back of the gas block to lock the first set screw in place. If you find out that you have rounded off the hex in the gas adjustment screw, we will send you a rebuild kit for the gas block that includes the adjustment screw, ball detente, spring and two set screws. No charge.
If you shot your upper a lot suppressed before trying to adjust the gas, it may have gotten carbon fouled and is preventing the screw from fully seating.
I recommend that you remove the handguard to access the gas block adjustment screws and remove the rear set screw first, then the side set screw, spring and ball detente. The ball detente is very tiny, try not to lose it. Then remove the adjustment screw and clean it of carbon. Then add a drop of oil on the threads of the adjustment screw and screw it in until it fully seats. Then unscrew it a little and re-screw it in a couple of times to see if it seats deeper. Re-assemble by installing the gas adjustment screw first, then drop in the ball detente and spring and install the set screw. While rotating the adjustment screw back and forth to feel the detente action, tighten the set screw until you can positively feel the detente click. Then tighten the set screw on the back of the gas block to lock it all in place. Screw in the adjustment screw until it fully seats, then back it off 8 clicks as a starting point for test firing and final gas adjustment to your specific ammo.
If you would like to, you can return the upper and we will do all of this for free.