Received:

br0: received packet on vlan1 with own address as source address

on router 1, when router 4, through router 2 and router 3, had a number of bridges assigned with eth0, eth1, eth2 eth3, wlan2, vlan1, vlan2, wlan0.1, wlan0.2, wlan1.0, wlan1.1, wlan2.1 and wlan2.2 or similar.  Just needed:

Assignment Interface STP Prio Path Cost
none eth0 Off 128 100 
br1 - VLAN-10-14-0-0 wl0.1 Off 128 100
br1 - VLAN-10-14-0-0 wl1.1 Off 128 100
br1 - VLAN-10-14-0-0 wl2.1 Off 128 100
br2 - VLAN-10-15-0-0 wl0.2 Off 128 100
br2 - VLAN-10-15-0-0 wl1.2 Off 128 100
br2 - VLAN-10-15-0-0 wl2.2 Off 128 100
br1 - VLAN-10-14-0-0 eth0 Off 128 100
br2 - VLAN-10-15-0-0 eth0 Off 128 100

Cheers,
Tk