vignetting anomaly

I took this photo a few days ago at Cape May, NJ. I used a lens hood because I had hard sunlight coming from the left. I generally leave the lens hood on all the time just out of habit.
It looks like I'm getting vignetting on both the top right and left in the sky in the photo, or is it just my monitor?

Shot with D7100 and 18-140 lens
f/5.6
ISO 200
Lens all the way to 140
1 /2500
Aperture mode.

It looks like vignetting to me and is probably there too in the lower corners. It's not uncommon and the wider open, the more it occurs.

Easily fixed in post processing.

Yes, fixing is not a problem. I just want to be sure that I'm not the only one that sees this, and it's not something going askew with my camera or lens.

Vignetting is good... I always add some in post... it focuses the eye toward the center of the frame/subject