[wieszcz]

The forum moderators have determined that banned addons (wiki) are present on your system. To receive assistance here, these banned items must be removed. If a clean log is not submitted within 3 days, then the relevant post(s) will be removed after this time.

 I am not aware of any addons except Youtube and Boblight (disabled) on my system (other than the ones on which these two depend on). Can you clarify? 

I have uninstalled Kodi, and got a new copy from https://kodi.tv/, so it shouldn't have any banned addons or programs.  Unfortunately the issue continues.
first log: Kodi is "windowed" , the problem starts and continues when the bottom control bar hides. I moved the mouse around 35s into the movie to close Kodi, the control bar showed and the fluidity came back 
https://pastebin.com/thNAa794
second Debug log: Kodi is "full screen 1" 1680x945 p, there is NO problem, no stuttering, fluid motion
https://pastebin.com/dq92xg7g
third Debub log, Kodi is "windowed" but I made the window smaller than my monitor (about 90%) - there was NO problem until I had expended the window to take the whole monitor (around 50 seconds into the movie), then I got the stuttering again.
https://pastebin.com/uMVL5PeH

I have played the same video from my hard drive in all three instances.