Hey Bill, thanks ! It was on ADV indeed. Just beginning with digital cams and with the X-T3, so still have to find out all the possibilites (like ADV). Nevertheless I'm happy it's nothing more serious.
Lens hood not mounted correctly?
Added screw in filters excessively thick?
Accidentally set your editing software to ignore or not apply lens correction settings?
It looks pretty severe, almost like an effect has been applied, like a Holga or toy camera simulation.