A few images taken using the Lee filter system (full size) on my XF14mm lens have featured a curious semicircular artefact. I thought at first it was flare but on closer inspection I've realised it is reflections of the lettering on the front lens flange. An example is attached - I've bumped up the contrast to make them more obvious.
There is (hopefully) an easy fix to this. I've applied some black tape to cover up the white letters. Checking through there EVF this seems effective but I'll try it on my next shoot and see how it goes. I haven't seen the problem with my other Fujifilm lenses (18-135 and 35 f1.4).
If anyone has encountered it before I'd like to hear their experiences and fixes if appropriate.