I'm not gonna lie; suiciding next to a bunch of archers sounds like a hilarious thing to do But none of these situations applied to me; it was a straight up ally throw bomb, no other bombs/rock around, he didn't die, I get blown. Haven't had it happen today though
Getting a video of it is more or less paramount - I literally haven't seen it in-game so can't know what's causing it.
That could be because of a bug where an enemy gets switched to your team but he/she is still an enemy. Could be....
Maybe, I felt like I was the culprit of this sort of thing today, a teammate of mine threw a bomb into 3-4 reds I was fighting, it blew up and I died (they didn't), it was definitely his bomb I saw him throw it, so I don't know what was up there, but everyone died, me and the reds, don't recall my death message and didn't get a video sadly. I could have been lagging and one of the reds picked it up and threw it back down without me seeing it while I killed them or something though.
Well when I see a griefer I've pulled a bomb out on them, and charged them before. It killed them. So probably the fact it killed me too, is the problem. As mentioned above.