Is it running well in all positions on the bench, before you put it in the case ? Just trying to rule out anything in the bare movement prior to casing.
And if that's a "yes", try loosening the movement screws a bit, and then move the movement ( cute, huh ? ) and see if it's an alignment issue between the movement and the crown/stem assembly. Maybe its just mis-aligned a bit, and binding.
Sorry if this sounds simplistic,..just trying to rule out what I think could be issues.