Laggy mouse cursor on secondary computer when fake mouse support in the settings on the secondary computer is active as of the last windows 10 update. I had to disable the fake mouse support on the secondary computer and it went away. This is a loss of functionality from last windows 10 update.
To be more accurate describing the issue I'm seeing: the problem presented as a second mouse cursor that stayed stationary for a second and then disappeared (like a snapshot of the cursor) where it was about every second. It didn't affect functionality, just super distracting and annoyingly obvious that something looks wrong.
I found the fix here: