doublevr i don't know if it's the 90--> 60fps conversion that somehow killed the framerate / made it buggy but it's just not as smooth as regular 60fps scenes. Dunno how to explain but i can see motion blur almost while regular "old" scenes (whether shot with the 6K or 8K rig) appear much smoother. It's not the Quest 3 that has issues playing it, i mean it does it with H265 and I have zero issue with non black magic 8K 60fps scene. This one just doesn't seem as smooth when moving.
I was so puzzled that I had checked my settings to see if i was indeed still running at 120Hz and went back to an old scene to be sure my Quest 3 was working fine.