I suspect this started after a recent firmware upgrade but my previously very reliable home network is suffering from repeated droputs of the LAN connection

I have a BT Smarthub 2 as the main router (DHCP Server) connected to BT Fibre to the premise internet.

This connects via wired ethernet cables to 1 X20 and 3 M5 units - the X20 is in the same room as the BT router and directly connected whereas the 3 M5s connect using ethernet backhaul using ethernet cables that extend through the house over MOCA 2.0 coax with MOCA endpoints that convert ethernet to coax to ethernet (better connections that using powerline)

All units are on the latest firmware.

Is there a known issue in the 1.5.x firmware that is responsible for this as it is driving me crazy.  Will there be a new firmware released soon to resolve this

(Note - whilst I have recently converted to the faster Fibre internet this issue started when I was preparing the local network for the switch over which is when I suspect I applied the firmware updates)

Initially I blamed the BT SMarthub which I placed into the network as part of the prep work.

IF there is not a known issue with the firmware then my next option is to use the X20 as main router and eliminate the BT smart hub - however this will require configuring IPTV on one of the M5 units to connect the BT YouView box - which currently works 'out-of-the-box' with the BT smarthub using a powerline connection direct to the hub