@aussieburger Soooo, I was informed that my “flipped mesh faces” bug couldn’t be repro’d by their engineers, but that it wound up being the same as Unreal Engine Issues and Bug Tracker (UE-77927) , so I guess go ahead and upvote that one if you are getting flipped mesh faces on Android in 4.23?
I’m not using “media player textures” at all, and I’m not sure why they couldn’t repro this one without them … but as long as it gets fixed I’m happy 
edit: One thing I did notice is that it only seems to affect skeletal meshes and procedural meshes in my scene. Static meshes are unaffected.