Based on the reported behavior, this sounds like the Tokina focus-clutch mechanism not fully engaging every time rather than a Nikon body fault. With these Tokina push-pull AF/MF rings, you generally shouldn’t need to align anything special, but sometimes the clutch may need a slight wiggle to seat fully.

If the ring feels stiff after switching, don’t force it. Slide the ring again and gently jiggle it until it drops fully into the MF position. Users report this works most of the time, with occasional partial engagement causing the rough feel.

So yes: a slight jiggle during the push-pull switch can be normal on this design. If manual focus remains consistently hard even when the ring is clearly in the MF position, stop forcing it and inspect the lens or have it checked.

The community answer did not provide reliable detail on optical performance, so it’s best not to assume anything beyond normal testing of your own copy.