Sort of...
It's not unusual for modern Speedmaster Pro's with the Cal. 1861 to have quite high balance amplitude. Balance amplitude is the amount that the balance wheel sings in each direction, and for example I have one here with the amplitude in the high 330 degree area - right on the edge of what is known as "rebanking". Rebanking is a condition where the balance rotates too far in each direction, so the impulse pin strikes the outside of the pallet fork horn. These details aren't terribly important but the effect is that the balance bounces back faster than the balance spring would return it, and this cycle continues - it causes a temporary rate increase.
This is most likely to happen when the watch is fully wound, and it may stop fairly quickly after that. So yes it's possible that this is happening not as you are winding, but right at the end of winding.
This is more likely to happen with the watch dial facing up or down, so if you wind it with the dial in a vertical position, it will likely take enough amplitude off to not let this happen. You could also make sure that when you reach the end of winding, that you don't try to force the crown one more click.
Cheers, Al
Click to expand...