This is very unusual. If others in the same area are having problems and if they are exactly the same in background (ie new FTTP) then unless they each have router or other internal connection problems it does suggest some NBN fault at the 'Multiport' in the pit. But personally I have never heard of such a problem. If a fibre joint has been properly spliced there is little to go wrong, and the chances of them all having the same NBNCo subbie are probably nil. Are your ethernet cables (Rj45) firmly plugged in (NTD now to WAN on router)? If you are still having problems Mods might contact NBNCo to arrange a tech visit with an optical power meter, BUT intermittent faults are notoriously hard to pin down.
There are two ways of eliminating your router from your investigations. You could try connecting a laptop straight to your NTD using your RSP credentials. You could also try a hotpsot. But neither is practical for intermiitent dropouts.
