Squads mode crash when not party leader? Weird one

Finally have a teammate to do egg runs with, and he was crashing constantly (like 3+ per run) despite having a 4080 beast setup. We thought it was one of the many crash related problems, and have slowly cycled through solutions, but it was consistently every squads/no fill game no matter what we've done so far.

Then last night he was the host for once, and I was crashing a few times a run despite it running perfectly when running solos. When we noticed this, we experimented and switched me back to hosting a squads/no fill game, and he was back to crashing.

The crashes were with Direct X (we've tried the updates and downgrades), and full BSOD's, on gamepass versions of COD. He's on a NVME drive and I'm actually running it off an external old 2.5" or 3.5" drive hah.

Anyone else run into this? I haven't found any info on it, and never had network related BSODs before