screenshot result thumbnail is squished

Observed behavior: The Screenshot app shows a thumbnail of the image in its save dialog box. The image is sometimes squished, like its aspect ratio was not preserved. I note it most often when using the "window" screenshot function, and the error is usually the correct x width and shortened y length. I've seen other graphical errors.

Expected behavior: The image should show in its proper aspect ratio.

I'm unable to reliably reproduce it, but if I take a bunch of screenshots, at least one in the handful does it. It's hard to screenshot the screenshot result since my screenshot keyboard shortcuts are not working properly either.

Loki, nvidia 367.