Great insight. I had not noticed that the cursor tracks just fine with the built in track pad.
It's my magic mouse and keyboard that are laggy on just 1 of my 2 extended monitors.
Was fine before Sequoia
.
If it weren't so aggravating, I'd limit what I put on that screen and move on but..oh man it's bad.
Seems to be displayLink/Sequoia and not my hardware (keyboard/mouse fully charged)