One of my connections with Orcon uses the NF4V but don't have this issue and have a somewhat complex LAN.
I did have issues in the beginning, so I got a Netcomm firmware, not an Orcon one and flashed it :) No dramas since but use with caution when flashing as usual advice goes.


Anyway, for those with the issue does web UI menu for ARP or syslog show anything at all on the modem/router, tried wiresharking it?
Anything at Layer2, advertisement solicitation or broadcast floods? bare in mind you use a non managed switch and make a spanning tree loop, well do I say more? But I doubt this is the case if there's a sufficient amount of people with the issue, small guess just on people saying "complex lans" they have.

Otherwise visit http://192.168.20.1/enginfo.cmd (replace the IP if required to your modems) if your handy with Linux, for some other info if you need it.
slab (proc) would have arp_cache present normally.


I prefer to ssh to my nf4v, the below will work (enable SSH in modem first) if you want data dumped via shell and not web.
"arp -a"
"syslog dump"

This may indicate if the arp table has updated. Seems it may not be flushing and updating based on various peoples 'symptoms'.

If I have the problem wrong/off course or this advice of mine has been done somewhere else in another thread - apologies.