Test requirements and code are similar across test items for SBSA (430) and BSA (830). Why did the test pass in SBSA but fail for us with the BSA equivalent?

Though the tests are the same,  the checks are made on different devices in each case. 

SBSA tests are run only on RCiEP and  iEP/RP devices

BSA is run for Root Port and End Point. 

In the case where the the failure is in the BSA tests - this would suggest a failure in End Point devices.