BitLocker Network Unlock Question

I set up network unlock for two servers in our network as a test for a future deployment of BitLocker.  Both HP's.  One is a DL 360 Gen9 server with aftermarket TPM, the other is a DL360 Gen11 with onboard/HP TPM.  Configured first NIC on both boxes for DHCP.  Just to test things, I unplugged NIC1 but kept NIC2 plugged in on the Gen11 server and rebooted.  It prompted for a PIN on boot up (expected behavior). 

Did the same test on the Gen9 server and it boots straight into the OS (unexpected behavior).  As a further test, I kept NIC1 unplugged and then unplugged NIC2, rebooted and got prompted for a PIN (as expected since box was completely off network).  

Does anyone have any ideas why this is happening?  Could it have something to do with the aftermarket TPM?  From what I've read network unlock requires the first NIC to be DHCP so it can communicate with the WDS server and allow network unlock to work.  Could it be something with the NIC's on the Gen9 server?  I'm at a loss to explain this behavior.  Hoping someone may have some insight.

TIA