Devices on 2.4 GHz and 5 GHz cannot see each other

[rjvhmm]

Home network has a mixture of 2.4 GHz and 5 GHz devices, all devices were able to see each other and communicate with no issue on our old C7000|AC1900 Cable Modem Router.

Upgraded to a new Netgear Nighthawk X4S-AC3200 (C7800), now all devices on the 2.4 GHz band cannot see or communicate with any of the devices that are on the 5 GHz band, it's as if they were on two completely differnent networks, not different bands on the same network.

Has anyone else in the community experienced this, or is this a known issue and/or is there something in the settings of the Netgear Nighthawk X4S-AC3200 (C7800) settings that we missed?

Any information would be greatly appreciated.

[welmandouh]

I have the same problem and need an urgent solution. Also when I connect using cable, some computer go under the 2.4 and some go under the 5 and don't know why.