MPO files are basically two layer jpeg's used in 3D photography. These two layers represent the left and right view of the 3D image. I regularly open MPO's in Photoshop for editing.
The problem is...
Adobe has been treating these simple layered jpegs as some kind of 3D object that needs to be rendered. Adobe has made clear that they are removing their 3D processing from Photoshop and it looks like MPO support may suffer from that.
Please...
Separate MPO's from "3D" and allow us to open them directly; as the simple two layer jpeg that they are. They never needed that extra "3D anaglyph" processing.