ECMP is not supported for BIER in 7x50. For BIER OAM, Multipath Entropy data sub-TLV of Downstream Detailed Mapping TLV is used for ECMP discovery. SR OS does not support the Multipath Entropy data sub-TLV type. If SR OS receives Multipath Entropy data sub-TLV in the BIER OAM packet, it responds with the return code "One or more of the TLVs was not understood".