Joining survives a handover
Someone let into a team just before its coordinator handed the role to another member now still lands in the team instead of being turned away.
Opening an invite lets you straight into the team. If the answer had not reached your Mac yet when the coordinator handed the role to another member, the next try came back looking like it was from a different team and the join was turned down, even though everyone else already counted you in. The Mac that let you in now answers the way it did when it let you in, so the join finishes and the new coordinator is picked up right after.