Description of Bug: There's several things that happen, with the main thing being that once you fireset the rocks you have, you're only able to pour water over them once before you're not able to do it again. It takes water from you, but it doesn't open any rock in the pile after you do it the first time.
Reproduction Steps:

1.  clicking and dragging a barrel or a cup/bowl of water over a fireset pile of rocks once
2.  step 1 a second time afterwards
3.  dragging the rocks occasionally makes it work but it's still a struggle to get them to open.

(also unreproducible extra: in the process of trying to open these rocks my oven vanished)