Similar item clumping in Jera break

I was doing a Jera + Blank Card break, and I came across a stone chest, which had an item in it. Soon enough, the entire room was filled with stone chests. I began bombing them and creating little circles of items. One of these circles was entirely Zodiac items.

Every single Zodiac clumped together in one little explosion. There were no other items in the clump. Is this just coincidental, or could it be that the game is emptying out the pool in a specific order, and those are clumped together?

I also found Bobby Bomb, Mr.Mega and other bomb Items clumped together in an explosion as well. It could also be that since the chests open simultaneously it doesn't have time to randomize the next chest and it chooses the next option in the pool, which would be arranged that way. I've never had this happen in a normal (key chest/red chest) break.