Damned GL.inet SFT1200 device. It claims a lot of external IP addresses as pointing to its own uplink MAC address, even when used in WLAN connected repeater mode, set as router (aka as WISP mode). This feature does exist for the LAN ethernet interface, as "DROP-in gateway", but it's not activated here, and it is not for the WLAN uplink interface. My Hotspot (Mikrotik) dynamic mode is triggered to NAT some of the leaked SFT1200-LAN addresses (192.168.8.x) to it's Hotspot normal range (where the SFT WLAN address is part of, as it got is from that Mikrotik DHCP). It sees too many MAC/IP links in DHCP and denies access.
Only wireless is used in this setup, no ethernet cable attached.