Spread Daemon stops sending and receiving messages while showing increasing number of retransmission

I have a setup with 6 devices (running spread 4.4.0 on linux) with each one configured on a separate segment because they are located on separate subnets. Multicast and broadcast is not available so I configured the segments as follow
			
Spread_Segment  172.23.1.1 {
  node1   172.23.1.1
}

Spread_Segment  172.23.2.1 {
  node2   172.23.2.1
}

Spread_Segment  172.23.3.1 {
 node3   172.23.3.1
}

Spread_Segment  172.23.4.1 {
  node4   172.23.4.1
}

Spread_Segment  172.23.5.1 {
  node5   172.23.5.1
}

Spread_Segment  172.23.6.1 {
  node6   172.23.6.1
}

Everything works perfectly 99.999%  of the time but it happened a few times that we had a situation where all the communication between the nodes were stalled and looking at spmonitor we discovered that some daemon were constantly retransmitting.  There was no way to get out of this mode besides restarting the daemon. During that time all communication between the nodes were work fine on all other ports (ping, 22, http, and some other udp port that we use). 

My Questions are:
- Why would that happen ?
- Is there a way to detect it and to resolve it without restarting the daemon ?

Thanks 

Claude