https://www.thebalance.com/what-is-procuring-cause-1798896
he "procuring cause" of a real estate transaction is the agent whose actions and efforts result in the sale of a property. It's the agent who ultimately caused the buyer to purchase the home. As such, that agent is entitled to compensation in the form of a commission.
You don't have to hop from real estate agent to real estate agent to end up causing commission disputes over who is the procuring cause....