Hidden block quick rule dropping CARP advertisements

[apomeroy]

I have a pair of pfsense 2.6.0 firewalls with six (6) VLAN interfaces that have CARP VIP configured. When CARP is disabled on the primary firewall, the VIPs all successfully migrate to the backup except for the fifth VIP (re2.501) which remains as Backup mode on the secondary firewall. Checking the firewall logs, there are block drop messages from a hidden/built in rule that occurs prior to the CARP pass rule or any user rules.

pfctl -s rules snippet:

block drop in log quick proto carp from (self) to any ridentifier 1000000201
pass quick proto carp all no state ridentifier 1000000202

only block log messages (10.3.5.101 is re2.501 interface on primary):
Jul 8 16:41:09 LAN-D (1000000201) 10.3.5.101 224.0.0.18 CARP 105/0/1
Jul 8 16:41:09 LAN-D (1000000201) 10.3.5.101 224.0.0.18 CARP 105/0/1
Jul 8 16:41:09 LAN-D (1000000201) 10.3.5.101 224.0.0.18 CARP 105/0/1

pfctl -s rules | egrep carp

block drop in log quick proto carp from (self) to any ridentifier 1000000201
pass quick proto carp all no state ridentifier 1000000202
pass in log quick on re0.101 inet proto carp from <fw_wanmgt_addrs> to <fw_wanmgt_addrs> keep state label "USER_RULE: wanmgt carp" ridentifier 1688764914
pass in log quick on re0.201 inet proto carp from <fw_wandata_addrs> to <fw_wandata_addrs> keep state label "USER_RULE: wandata carp" ridentifier 1688765257
pass in log quick on re1.301 inet proto carp from <fw_dmzdata_addrs> to <fw_dmzdata_addrs> keep state label "USER_RULE: dmzdata carp" ridentifier 1688765300
pass in log quick on re1.401 inet proto carp from <fw_guestdata_addrs> to <fw_guestdata_addrs> keep state label "USER_RULE: guestdata carp" ridentifier 1688765329
pass in log quick on re2.501 inet proto carp from <fw_landata_addrs> to <fw_landata_addrs> keep state label "USER_RULE: landata carp" ridentifier 1688765356
pass in log quick on re2.601 inet proto carp from <fw_lanmgt_addrs> to <fw_lanmgt_addrs> keep state label "USER_RULE: lanmgt carp" ridentifier 1688765382

Not sure why there is a problem with that one interface/VIP, the setup steps I've taken are:
Primary fw:

• interface assignments
• VLAN assignments
• CARP VIP assignments, one per interface
• CARP, 443/tcp, icmp allow rules on all primary/secondary fw interfaces
• pfsync allow rules on re2.601 primary/secondary fw interfaces
  Secondary fw:
• interface assignments
• VLAN assignments
  Primary fw:
• HA sync all

Primary and secondary firewalls have dedicated switches for WAN, DMZ and LAN physical interfaces.

What other information would be helpful to post here to troubleshoot?