Last minute join

OK, idk if it coincide but this has happened for most of my hunts. People always answer my SOS call whenever the monster is in its final phase. They join, attack a little and then boom, monster defeated and they get to claim materials for free. Like, I don't mind but it's getting irritating. Sometimes, they join when the boss is already defeated...like they join just to carve and dip. No hate from me, just venting. Anyone else experience this?