Grid pattern on darker footage

I've been working on a project (with a mix of Pro Res and BRAW footage) for months now. After working on color last week I noticed a weird grid pattern appeared on some of the under-exposed Pro res footage. When I pause the footage the grid sort of goes away, but it's there when it plays and still there in the export.

I took all color correction, grading, and fx off, changed the Resize Filter (the footage is 4k in a 2k timeline), and tried exporting in a variety of codecs.

I've seen others on the forum with a similar problem during editing, but none where the grid pattern is still there in the export. I attached a photo of the problem color grade off and on side-by-side (high contrast to help see the grid).

I'm running Resolve 16

Computer Specs:
iMac Pro (2017)
3 GHz 10-Core Intel Xeon W
64 GB 2666 MHz DDR4
Radeon Pro Vega 64 16 GB

Odd side note - exported a different file shot on a different camera from a different project as a pro res 422 from DaVinci and brought it into an FCPX project, and in that export from Final Cut, the grid appears as well. Hasn't happened with any other FCPX exports though.

Any way to test using an nVidia GPU?