[noggin]

Please tell me your experience with variable frame rate videos and the "adjust display refresh rate" option on.
In my case, Kodi changes the display refresh rate back and forth when there is a transition of frame rate.
For example, with:
Minimum frame rate: 17.118 FPS
Maximum frame rate: 29.981 FPS,
"adjust display refresh rate" set to on makes it impossible to watch.
If I disable it it's OK.

What happens if you just have adjust refresh rate On Start/Stop enabled, rather than Always? 
What's the source of the variable frame-rate content ? I seldom see any variable stuff these days.