Snapping/clicking in left scapula during Shield Casts

I've got this snapping sensation in the scapula during Shield Casts (left side only). It happens at the transition behind the neck when I start the pulling phase of the club to the front.

There is zero pain, but the 'snap' is noticeable. Any advice on form corrections, or is this something that resolves with more volume?

my right side is totally okay.