Adding a note, it's on samsung s6
Created attachment 8842259 [details] Samsug Galaxy s6 screenshot Looks the same to me on a Nexus 5x, Samsung Galaxy S6 and Firefox on Windows. All tested with the current nightly v54.0a1. Would you try the build from https://nightly.mozilla.org or https://play.google.com/store/apps/details?id=org.mozilla.fennec_aurora and let us know if those work.
ok, seems I don't get the error anymore. Tought it was that error causing the blackness on https://sketchfab.com/models/8d06874aac5246c59edb4adbe3606e0e/embed?autostart=1&graph_optimizer=0&merge_materials=0 on firefox android (firefox desktop or any other browser is fine) ( posted that osgjs light as simpler repro case, but seems it wasn't a good one)