I haven't pinned down the exact cause, but bowls often act really strangely. I think most of the "problem" bowls have been pre-hiatus bowls, though I don't know if that's coincidence or not.

However, I've noted down a list of things that have occurred and keep occurring, although it's inconsistent at times.

• Bowls with pestled herbs disappear when adding ingredients to a pot, cup, or vial
• Said bowls sometimes re-appear (usually after server restart) with their pestled contents as if they had not been used
• Empty bowls will behave as if they are full and not allow anything to be put into them
• Bowls will only allow one from a stack to be picked up. If attempting to grab the whole stack, the bowls vanish until server restart