What don't I like? The fact I don't have a second 50R body as I'm trying to sell some of my X bodies and lenses. LOL. Oh, and the fact the rear LCD doesn't articulate properly when the camera is in portrait orientation. That's it.
I would check in with fuji suppport in your area but to me, and I'm no expert, it looks like Like leakage -- of which there should be NONE.
I've shot with the 50R uptimes o ISO 6400 and have never seen this.