Lucy Thank you for the response, I see now these naming rules!
I tried with the naming: " Project_SPATIAL_TBE_8_2.mkv " but it did not work.. Skybox detects an Opus 10 channel audio, and the sounds are "sounding", but not in a spatialized way. Also, in that FAQ page, there is a symbol (') right before TBE. Is that a typo? Hope this can get checked.
Just to be clear: my video is encoded via fb360 encoder, using .mkv option, with 3rd order ambisonics spatial audio + head lock stereo, resulting in a 10 channel opus (8 channel ambisonics + 2 head lock).