(Also replied to you directly; this is just a copy of my mail.)
This is only a warning message. It’s a warning that explains that some things may be mis-rendered in VR; namely, any component with the “cut opening” set on it (“Découper l’ouverture” in a French sketchup) is rendered as if it didn’t have that flag. You can ignore it if it doesn’t really visually impact your model.
Maybe we should add a checkbox “Ignore this warning in this model”, so as not to give you the same warning from the same model again and again.
Of course a proper fix would be to support it correctly in VR Sketch. It’s on our to-do list, but low priority so far.