This isn't a serious bug, but is quite amusing.

When your ship collides with objects, an INVENTORY_UPDATE event is generated. This has been reported by multiple users of the MAID plugin, including myself.

Are you sure the event isn't only being generated when new ore goes into your cargo hold? (ie. when mining)

Oh, yes. Register the INVENTORY_UPDATE event and then smash your ship into something (~100m/s).

But your inventory changes when you lose armor.

aye, logical point maalik.

yeah, your ship is considered part of your inventory. So getting damaged causes an inventory item update for the ship. I believe shooting a weapon that has finite ammo also generates an inventory item update for the weapon.