Nighthawk C7800 - Cutting Out During Red Dead Online Events.

[NiveusT]

On wired and wireless connections, roughly 5 different computers disconnect from events on Red Dead Online events. More specifically (Call to Arms) event. (I know it's weird we have 5 computers with this game on it, but our friends come over for little lan parties and stuff sometimes. Lol)
Nighthawk connected directly to the Coax. All wires associated with the internet are in good condition. No splitters to the Nighthawk.
Checked each individual computer for updates on wireless and other drivers. There are no firmware updates.

Trying another router- I do not have this issue.
I have contacted Cox and they said they have no disconnects on their side. The internet is up n' fine.
I tried opening ports, enabling/disabling Upnp, and turning off firewalls. We do not have VPNs on any of these computers.

No packet loss seemingly.

Assuming that this is the router itself. Is there anything I can do to check further into this issue with the router specifically?

[FURRYe38]

Tried a factory reset on the modem and setup from scratch? 

Does just 1 PC gaming experiences this issue while gaming? 

Do you have all these PCs connected all at the same time to the back of the modem when gaming? 

Have you tried putting in a Gb LAN swtich in between the PCs and the modem? 

One way to find out would be to put the modem in to modem only mode, connect up a diferent wifi router to the modem and then connect your PCs to this router. Does same thing happen? If not, then possible the router side of the C7800 can't handle that many PCs all gaming at once. 

[FURRYe38]

Any updates or progress on this?