HP DL380 G8 Fan #6 Running at full speed when server is powered off

I have a HP DL380p G8 with all supported HP hardware installed, this includes 2 300gb SAS HDDs, 1 1.2TB SAS HDD, and a HP SFP+ add-in card for networking.

When the server is powered off and is still plugged in, fan #6 only runs at almost full speed. HP iLO does not report fan speeds (among other things) when the server is off.

Server is in power saver mode in both the bios and OS.

Anyone know why this one fan would be running and at such high RPM (relative to powered on state)?

The SFP+ daughter card I had installed (HP Flexfabric Network Card) apparently ramps up a single fan (#6) to cool the card when the server is off.

Replaced the SFP+ card with a regular 4 port RJ45 NIC and the fans arent even spinning when the server is off.

Honestly, it doesnt make any sense why a single fan would need to be at such high rpm to cool a nic that should be seeing very little traffic and be running a lot cooler compared to a server with a workload running. The fan speed for #6 when the server is powered on (and the NIC is much more active) sits at 12% (barely audible).