Bad play head lag

I’ve been experiencing very bad play head lag while moving the mouse OVER THE INSPECTOR AREA using Cubase 7.5, 8 and 8.5 on fresh install of E Capitan and Yosemite .

  1. load an audio file on a track
  2. hit play
  3. move mouse cursor around screen ( specifically over the inspector area)
    –playback cursor stutters horribly

Cubase 7.5 video: https://youtu.be/3S2_KaPaJKY

Cubase 8.5 video: https://youtu.be/a2zddmf1S58

My system is iMac i5 27 inch 16 gigs ram. Using UR 28m with latest drivers.
Btw no graphics issues with Logic X on same system.

Problem known for a longer time now. Still not fixed in 8.5.20. Same problem is on Windows as well.
What actually helps is to turn of snap to zero crossing and the vertical cursor line for the tools.