Press hanstand transition

I have a shoulder issue that I'm hoping someone can tell me what's going on.

I currently straddle and pike press from standing on the floor and am trying to build the transition from L-sit. When raising from L, I seem to get stuck with hips just above horizontal. When doing negatives, I've found that both shoulders give an audible pop, as I lower through this position. The shoulder feels slightly unstable for a second almost like the ball jumps in the socket as it rotates. I have stopped training the transition until I can figure out if it from bad shoulder positioning, insufficient strength, flexibility or some other reason.

I try to lift the hips first but I know I am planching due to insufficient hamstring flexibility.

Should the shoulders be extended whilst lifting or only once the torso is vertical?

Hopefully someone understands what I'm talking about.

That momentary destabilization doesn't sound good.

The first thing that comes to mind is to try some cable lifts and dumbbell lifts so you can isolate the transition and play with the various ways of moving to eliminate the violent popping.

From L-sit you obviously won't have your shoulders shrugged up like in handstand, they have to transition there along the way.

Thanks for your reply.

I have done some stretching and found that my shoulder flexibility is low. Inlocate/dislocates with a broom handle highlighted that I have limited ROM. Looks like the extra leverage from lowering from handstand is enough to force the shoulder through despite the inflexibility, causing the ball to move in the shoulder socket. I'll be doing more shoulder prehab and stretching before continuing any further.