Is my 24-105 F4 lens defective?

I have been shooting with this lens for about a year now and have been happy with it overall. I have noticed that in specific lighting conditions I get a faded area on the right side of the frame. This happens in the outdoors, usually in high contrast scenes with the light source somewhere in front of me, but not necessarily in the frame of the picture.

At fist I just thought it was something similar to flare. However I have noticed a pattern that it only happens on the right side of the frame, never the left hand side.

Can you let me know if this is a defective lens I need to get fixed, or is it just coincidence that when I have had the right conditions for it to appear that this faded area is roughly always in the same spot?

Thanks

It is a bit strange, maybe there is some light leak that I doubt.

Did you try to carefully clean both sides of lens ?

No filter on the lens.  That is a good idea though.

It certainly looks like flare, but impossible to tell from just one image. I would have suspected a filter, but you say no filter was used.  Try testing with sun in the frame, or just outside, at different focal lengths and apertures.  Often easier to see in the viewfinder, especially when moving the camera around.

Meanwhile to rescue the image, if you have LR or ACR, try a radial filter with a touch of dehaze over the affected area. Or similar tools in other software, and used subtly - possibly with several passes - is the key to dealing with a large soft flare spot.

I cleaned both the front and back element and and shot photos with the sun both in the frame and outside the frame at different focal lengths. I was able to get flare, but not the phenomenon I showed in the photo in the first post. I have had this lens for about a year now and have only had it happen on 3 or 4 days on a handful of photos under specific conditions.

I did rescue a couple photos with a method similar to what you described. Fortunately no 5 star photos have had the effect.

I guess I'll just have to look out for that when shooting in the future and see if I can identify a pattern, or maybe it is just flare under a specific condition that I just haven't had the right conditions to have it show up on the left side of the frame.

Thanks everyone for your help.