Crown slipping question

[mcshal]

Hi there, thought I'd ask here first. I've got a 6427 (manual wind 34mm) that runs like a top, BUT.. I just took it in to get a new crystal and a new crown tube and since it came back it seems to have a good bit of crown wobble in the winding position, and of more concern, the crown slips when winding (like it's disengaging). It doesn't happen every time but happens pretty regularly. Could this be a product of reassembly, etc. during the service? And what could it indicate?

Thanks for any help you can provide, much appreciated.

Matt