I am having an issue where my devices even though directed via connection preference which deco to connect to are connecting to random units, and usually the one providing a weak to medium strength signal. I have rebooted the sytem and devices yet still end up with the same outcome.

Units are connected as follows: X68 main unit centre of house, wireless to next X68 unit at rear of house and that connects wirelessly to the next X68 unit in a building at rear of property. I also have 2 X20 deco's at each corner of the front of house and they are connected by ethernet to main unit in centre.

An example of the issue is a device at rear of house connecting to front units even though rear unit is with in 2m of it. Solar inverter and cameras at very rear of property bypassing rear unit and connecting either unit in rear or centre of house unit, even though it has been set via connection preference to the correct unit.

Iot devices use the IoT network and main WiFi is used for tablets/phones etc Guest network is not active unless I have people staying. All desktop computers, tvs and gaming consoles are connected via ethernet through main part of house. No ethernet at rear of house or rear of property, hence why wireless X68 used there and X20 at front of house. All wall are 20/30cm thick stone/concrete which is also why extra units as coverage is weaker due to building structure.

I have provided as much detail as I can think of. Any suggestions on what is causing this and how to rectify it would be greatly appreciated.