BIER MVPN only generates a single VC label and PMSI for IPv4 or IPv6 traffic belonging to the same VRF.
The BIER header protocol is set to "mpls packet with upstream-assigned label". This label is the VC label identifying the VRF that the packet belongs to. After finding the VRF and removing the VC label, a second lookup on the IP header identifies the packet address family (IPv4 or IPv6). Based on the destination IP, which is the multicast group address, the packet is forwarded out the appropriate MVPN OIF SAPs.