Lower level teams can purchase drivers and staff at significantly lower prices than higher level teams. This means that if a lower level team buys your driver, you only receive the amount they paid. For example, a level 5 manager might buy a level 39/40 driver for 5 million, while a level 39/40 manager could pay as much as 36 million.
I've sent the money and have found a potential fix for this. It is a bug, the high level manager should get the higher amount, while the low level manager pays the lower amount.