Weird Pro Res Video Export bug in CC 2018

Something weird I noticed exporting a project that's 1080, square pixels. Tried to export as Pro Res HQ, but the error repeated for all Pro Res formats.

So the output aspect ratio was getting squashed from 1.0 to .98something. It still read as 1920x1080, but it was noticeably smaller in the preview window than the source file. So I tried a few Pro Res formats, same thing. I switched over to a DNxHD format for output, it switched over fine and everything was as I would've expected, 1920x1080, 1.0.

So then I got curious. Switched back to Pro Res, and now it was slated to output at 1.0.

That's a weird bug, which would likely have created some HUGE headaches for me down the road if I hadn't caught it early in this process. Anyone have a similar experience?

Adobe, you guys aware that that's not a normal behavior?

Mike