RF 100-500 background distortion ? Please help

[ksmithson916]

I notice that most of my shots have this lateral line distortion in the foreground and background, is this a defective lens?

pics attrached

[ksmithson916]

btw, I through on my other Zeiss brand UV filter with T coating and the problem was still resolved, it was just that brand of filter. I not only trust Zeiss UV filters.

[jrhoffman75]

Sometimes there can be reflections off the front element of the lens that bounce back to the rear surface of the filter. Good coatings should handle that, but not always.