Actually, we too have issues with 650FLB and NPIV in order to run Virtual Fibre Channel in VM's on Hyper-V 2012 R2.
We are able to create SAN Fabrics, however - our VM's make the destination host crash when trying to Live Migrate this VM.
I've created a support thread here as well : https://community.hpe.com/t5/ProLiant-Servers-Netservers/HP-FlexFab-20Gb-2port-650FLB-Adapter-Crashes-Hyper-V-Host-when/td-p/6915011