Most likely a hazing prank gone wrong. Having 2 Raider and 2 Seals messing with a GB, most likely they're part of some sort of Delta unit, nonconventional. I think it was (most likely) accidental, but theyll burn.
Something about the story doesnt wash for me is, SEALS from Team 6, which has changed its name to DEVGRU (as far as I know) are the top 1% of the top1% of all seals and are hand picked in the try out process for DEV.
Seems unlikely for them to break opsec and be stealing, anything is possible but just feels well, too far out of the scope of any team guys ive ever worked with.
The Raiders, while they didnt exist in my day, and we didnt have a seat at the SOF table back then i cant comment. I will comment that any, and I mean ANY JOINT OP I did, we were scrutinized beyond enth degree. No one (in my experience) would be in a joint op and do something to give the MC a black eye, not at that level.
Anything is possible, just from my experience, the story doesnt wash well.