The first image is a still pulled from the color module in Davinci Resolve, and the second is a crop of that image showing the issue.
Video info: 10bit 422 HEVC internal, Clog3, Rec2020 color space, 4k120, iso 800
The artifacts appear in other clips of the same scene, but do not appear in 8K RAW footage of the same scene. Is pixel binning in the 4k120 mode to blame? I've shot that mode a lot in the past, and never noticed an issue.
Even if it is a reflection, it shouldn’t appear that way. It doesn’t look like a clipped highlight at all. And it’s not an issue with resolve, as it shows in premiere as well.
I’m going to conduct some tests back home to see if I can replicate this issue.