Issue with Network Stability

Hi guys hoping someone may be able to give some advice. Over the past few months I've been getting stability issues on my network, with multiple key units flashing blue orange when trying to turn on/off a load.

The issue is intermittent and gets worse over the course of a week. When it starts its the occasional delay in turning a light on/off, followed by the flashing blue/orange. If I power down the whole network that is all power supplies turned off and turn it back on it seems to be ok for a day or so, but then progressively gets worse. When its playing up scanning the network in tool kit takes for ever with lots of no response messages, but when stable everything scans no problem.

I have made the obvious check to see that the voltage is fine on the network, and I can see that for the most part every device is reporting between 29 and 32volts, with the ones at the lower end the most distant. I have also checked each power supply (I have two) and have also unplugged the network cable from each of my output units that have power supplies to see if one of them is causing issues but it never seems to help. I have also checked that none of them have the burden enabled.

I have also checked the outdoor PIR's to ensure there is no corrosion on any of them, and all are dry and look as good as the day they were installed, which is coming up for 10 years now.

I have tried to use the diagnostic program to see what I can see, but its not really telling me much. The traffic analyser is showing that I have burst of errors, but no indication to show what might be causing it and the reliability test when left running for a while shows most devices eventually get outside of acceptable limits, however assume that because what ever is causing issues is preventing comms to other devices.

Only thing that stands out to me is toolkit is reporting I have 1 burden too many, but for the life of me cannot work out how (or why when its been fine since installed). And don't laugh at me, the only burden I know of is in an old Minder! (which I still use and love to this day)

Any help or assitance would be great. Had Cbus for 26 years now (10 in this house) and first time I've had an issue like this!