Arista/EOS, MLAG ipv6 partial traffic loss

Topology (a typical MLAG network):

[mlagA] ======= [mlagB]
    \              /
     +---[Leaf]---+

Symptom:
1) about 10% L3 ipv6 traffic, WE and SN
2) No L2 or L3 ipv4 traffic loss

Get one problem destination - 2000:120:4d:d::1

1) show ipv6 route is good,
bn303.mlagA.profA.16:17:04(config)#sh ipv6 route 2000:120:4d:d::1
 C    2000:120:4d::/48 [0/1]

       via Vlan2077, directly connected

bn302.mlagB.profA.16:17:03(config-if-Vl2199)#sh ipv6 route 2000:120:4d:d::1
 C    2000:120:4d::/48 [0/1]
       via Vlan2077, directly connected

2) show ipv6 route host is NOT right
bn303.mlagA.profA.16:18:20(config)#sh ipv6 route host | grep 2000:120:4d:d
 A  2000:120:4d:d::1 on Vlan2077
 A  2000:120:4d:d::3 on Vlan2077 <<<<<< missing ::2
 A  2000:120:4d:d::4 on Vlan2077

bn302.mlagB.profA.16:18:20(config-if-Vl2199)#sh ipv6 route host | grep 2000:120:4d:d
 A  2000:120:4d:d::2 on Vlan2077 <<<<<< missing ::1
 A  2000:120:4d:d::3 on Vlan2077
 A  2000:120:4d:d::4 on Vlan2077

Root cause: 
missing configuration - "ip virtual-router mac-address mlag-peer"