Gateway outage on slave after master restarts

[shadowconnect]

Hello,

i've experience a strange behaviour, if i restart the master. First here is my setup:

WAN
                |
        ========
        |              |
    Master      Slave
        |              |
        ========
                |
            LAN

on the LAN-Side i've configured a CARP-IP, which is the gateway for machines on the LAN. On the WAN-Side i've configured a CARP-IP, which is used from the internet gateway to forward traffic to internal machines. The failover works fine, although the switchback to the master is also working. But as soon as the master is available again and i go to "Status" => "Gateways" on the slave, the WAN gateway is "Offline". If i now restart the slave, everything is working again and both (master and slave) display gateway as "Online". On both machines pfSense 2.3.1-RELEASE-p1 is installed.