Hearing additional "bang" with Speedmaster Pro

[B.F. Pigeon]

Hello all,

I really enjoy listening to the movement of my 2018 Speedmaster Pro. However, listening this morning for the steady ticking of the pallet fork and escapement, I now also hear a louder tick or "banging" sound over the ticking. Although difficult to describe sound in words, it sounds like a tiny hammer on a tiny piece of sheet metal.

The banging initially sounded steady, but sometimes it's irregular, and sometimes it appears to be gone. Please note that this is over the span of two hours after fully winding the movement.

Does anybody recognize such an additional sound? Could it perhaps be the mainspring or escapement giving of an additional sound whilst releasing the first power after being fully wound? Or could it perhaps be a normal sound that I just never registered before?

Any feedback/input would be very much appreciated.

All the best,

B.F.