I found something really strange in the log of the main router recently. It appears that the DCHP server is giving ip addresses to the other Mikrotik devices and imminently after that it de assign them. So basically the log is full of this.
The current setup is HEX S as main router -> 2x hAP ac^2 used as bridge APs. The main router has recursive dual wan fail-over. The other devices have no DHCP clients/server and no firewalls. All ports are bridged and they have assigned their own address. I'm starting to investigate this but I'd be glad if you have any idea what may cause it. Both devices appear to have same MAC when I check it from the console.