On a realm, my brother suddenly started dying to [Intentional Game Design] but there were no beds in play. (this was in the nether)

It was gravel being destroyed causing either him or the gravel to explode.

The first time it happened he got trapped in gravel, he broke it and it exploded. The most recent time he had broken a piece of gravel to climb up and it exploded and killed him

I couldn't get much image wise but I did include the chat and a screenshot of the blast zone. We tried recreating it but it didn't seem to work. This was in a Basalt Delta if that is important at all