[drdwridav]

Tvservice -S exactly the same
No change with the firmware swap.
Hope this is narrowing things down!

There is a problem in the HDMI spec.
To enable a 3D mode, you signal it in the AVInfoframe (out-of-band data transmitting during blanking periods).
The HDMI 1.3 spec didn't clearly specify how you switch out of the 3D mode.
The obvious interpretation is to say if 3D signalling is present then switch to 3D mode (if you are not in 3D mode) and if 3D signalling is absent switch to 2D mode (if you are not in 2D mode).

That has been clarified in the HDMI 1.4 spec to behave that way.

But I have heard of a few displays that don't switch out of 3D mode when the 3D signalling is removed. This is really a flaw in the display as 99% of displays do behave sanely.

But if you say your TV does behave as desired with LE 7.9.4 then there probably is some change we can make to fix it. Finding it may be tricky.

A debug log (wiki) from both Milhouse build and LE 7.9.4 would be the next step.

I think there is something a little ugly in the way kodi switches to 3D mode where it first switch to correct refresh then switches to 3D mode (see here).

I'd be interested to see if that sequence is different (or perhaps timing is different) between the two builds.

Hi popcornmix
Have sent you a pm with links to the debug logs.
Cheers

EDIT: one other quick finding. If I disable adjust display refresh rate -obviously playback jerky - but kodi does switch back to 2d properly on exiting. Interesting?