Insane moire with BMPCC 6K that was not present in-camera

Your shirt is exactly the kind of fabric that would cause moiré to appear on my Ursa Mini Pro and Ursa Mini 4.6K before I installed RAWLITE OLPF. Since putting them in, it hasn't been an issue.
I

So we can conclude the P6K is better than UMP and UM4.6K regarding moiré?

Higher pixel numbers drive the lenses closer to their resolution limits. The BMCC 2.5K was worse than the UMP 4K.6K regarding moiré. So, yes, theoretically you might see less of it if you don't have extremely good lenses.

. Got plenty of old glass hanging around for this lens downgrading gold rush.

I think at 8k it might be much better, as if you use my half pixel shift suggestion, it would act like a olpf when down sampling to 4k, even better 2k.

[CaptainHook]

I checked all my settings, disabled performance mode, have BRAW set to decode at full resolution, tried 1080/UHD/6K project settings, nothing is showing me what the people with Macs seem to be seeing.

Can you export your project and share that so we can look at your settings to double check?
Maybe someone like Jamie who is able to view it without issue can share his project so you can see his settings?
Unfortunately it wouldn't include the global settings but it's at least a start at trying to narrow down.

Also, how does the file look in the Blackmagic RAW player? Trying changing the window size as well.

[CaptainHook]

This is the OSX Blackmagic RAW Player for reference - it should appear the same on Windows.

Blackmagic-RAW-player-OSX.jpg (729.93 KiB) Viewed 1379 times