I'm having a bit of an issue with the boulder. On it's death animation, it doesn't break apart like a projectile might - it keeps spinning for a while before disappearing. And because it's called BoulderSling_Portrait.mdx, it messes up the catapult's portrait, showing a spinning boulder or a flickering gray screen instead.
EDIT: I fixed the portrait bit by changing the path name in imports. Can't do anything about the death animation, though.