This issue is resolved in VMware NSX-T Data Center 3.0.2 available at Broadcom Downloads
Workaround:
To work around this issue, restart the netcpa on the ESX transport node which has the BFD session down issue using this command
/etc/init.d/netcpad restart
Alternatively, reset the VMs. You can check the BFD session reference by a CLI command.
For example:
BFD count: 1
===========================
Local IP: 172.19.223.119, Remote IP: 172.19.223.120, Local State: up, Remote State: up, Local Diag: No Diagnostic, Remote Diag: No Diagnostic, minRx: 1000, mult: 3, isDisabled: 0, l2SpanCount: 1, l3SpanCount: 1
Roundtrip Latency: NOT READY
VNI List: 73729
Routing Domain List: ########-####-####-####-########740a
This BFD session is referenced by VNI 73729 and Routing domain ########-####-####-####-########740a. You needs to reset all VMs locating in this VNI/Routing domain.
Note: VMware recommends to restart the netcpad service as the first option as restarting is the simpler workaround of the two.