Skybox seems to work great for 2D content on my Vision Pro, but every 3D FSBS movie I play is cropped. These are all direct rips I've made from 3D Blu-Ray disks. They aren't cropped when using other players.
https://imgur.com/a/N2nDZxC
This is an example from Avatar.
EDIT:
Just tried the TestFlight build and it solves this problem, but now there's judder during panning shots. The judder didn't happen with the previous build.