[CompSci87]

Assuming the coaches had statistics showing that a quick second foul is common, there could be other reasons besides ref bias. The player might be upset and distracted after being whistled. She might be trying to do something extra to make up for the mistake and end up making another. The foul might be a sign of fatigue. All are good reasons to give the player a break to cool down and observe for a while. 

In addition, sometimes there aren't a lot of breaks in the action and players are waiting on the bench or even at the scorer's table for a chance to come in. So, often someone will sub out when a foul is committed. Sometimes it will be the player who fouled just because it was about time to sub for her anyway.

[CompSci87]

Assuming the coaches had statistics showing that a quick second foul is common, there could be other reasons besides ref bias. The player might be upset and distracted after being whistled. She might be trying to do something extra to make up for the mistake and end up making another. The foul might be a sign of fatigue. All are good reasons to give the player a break to cool down and observe for a while. 

In addition, sometimes there aren't a lot of breaks in the action and players are waiting on the bench or even at the scorer's table for a chance to come in. So, often someone will sub out when a foul is committed. Sometimes it will be the player who fouled just because it was about time to sub for her anyway.