Mark on images - any clue as to the cause please?

[FishyFish]

I got a roll of film processed recently that was shot through a Samsung Fino 60S compact. Most of the scans are showing a defect in the same place. It doesn't look like a light leak (although it could be, I suppose). I'm wondering if it might be some light getting in from the little window on the back of the camera (although the seal looks ok). Otherwise, I can't see any obvious issues in the camera or on the lens. Any idea as to the cause?

I'm more curious than anything - I'm not fussed about the camera as it didn't cost me anything, but I was thinking it might have been a good choice for another "Travelling Camera" type project.

You can see it at upper-left in the first image, and far more apparent at bottom right in the the portrait-orientation image.

 

[steveo_mcg]

Could it be something in front of the lens? Maybe a bit of the lenses zoom assembly come away?

 

[dmb]

I had similar round arcs on an Olympus Mju zoom especially in bright sun and tracked it down to a failure of the light seals on the extending zoom lens segments.

 

[john.margetts]

Your push bike could do with some oil, young man.