Well turns out I WAS WRONG and my old router just LAN kicked me aswell
Could this be a issue with the power?
Does your router uptime get reset when you get booted?
Was just wondering if a momentary drop in power could be causing your router to spaz for a moment and then you get kicked.
Are you using a surge protector or a trailing socket (with the router / modem / PS / or all of them attached to it).
Can you try using different power outlets?
And I assume you've already tried:
a new ethernet
dust blower in the PS port
checked that everything is 'clicked' firmly into place
If none of the above then I'd guess it's a faulty port/card in the PS (it's obviously not the Netduma or the other router as it happens with both).
If it was happening to me then I would connect a laptop to the router (over ethernet) and run Ping Plotter whilst I was gaming.
When the error message appears on the PS, you should be able to narrow down where the problem is occurring a bit more from the PP graph (by whether it shows packet loss or not).