I didn't see an answer to this one, but we know what happens if you drop a crystal due to damage onto an empty space, a minion, another mech, an impassible space (E.g. boulder), etc... The ONE case that we didn't see was what happens if a crystal lands on another crystal?
We called it that the rules don't specifically say that two crystals can't share a space, so the crystals just stack up. Naturally since a mech can't carry more than ONE crystal at a time, this may mean that they're standing on top of one crystal holding another crystal which is a bit clunky with the minis, but hey...
Has anyone seen an official ruling on this one?
I haven't seen any official ruling, but based on rules as written, I'd play exactly the way you state it.