Context
This are images from my recent air show. All was taken at (210mm, f/6.3, 1/1250, ISO100) using the 55-210/4.5-6.3 lens on my Sony a6000.
Question
Is that vignetting or something else happening to some of my images? I often see the vignetting similar to the 2nd image from the top but what is going on in the 1st and 3rd image?
Update
No filters are used in the shots below and the images posted are the full image just scaled down. For shot #3 that was in a burst and only that shot, out of the others, has that issue.