I noticed the other day that there appears to be a slight discolouration on the rear glass on one side. I’m not sure if this is something on the glass causing this but whatever it is it won’t clean off. It’s quite noticeable under any lighting and when wiping with a damp cloth it seems to hold on to water and reveals exactly where it is. I wonder if it’s a patch of oleophobic coating missing or something as it seems slightly more grippy in this area than others. The area circled in red is the patch I’m talking about (difficult to catch on camera but you can just about make out a line in this circle where there is a colour difference) When wiped with a damp cloth Any ideas?