What exact version of AE are you using?
If it's not 11.0.4, you're missing some important bug fixes.
I am running After Effects 184.108.40.206.
And this happens with the slider scrubbers too - not just the move "tool" in the Comp viewer.
For instance, I just went to scrub spin dial in a Rotation value and as I rotated the layer, same thing - sticky stuck at the start and then fine fine fine so long as I kept dragging but then as soon as I slowed down enough or paused, the layer stuck again as it rotated in the viewport. It's like it's quantum jumping - it's just popping to a position / rotation instead of travelling there...
Huh and a Zah. Huzzah.
I changed my Nvidia settings from Quality to Performance and made the "Preferred Graphics Processor" the Nvidia card ... which of these did the trick I do not know but the lag is all gone. I had even started noticing it in other programs (drawing a marquee in Photoshop, viewport orbiting in Softimage..) but now it's universally gone. Fingers crossed.