CAX30 5ghz issues

I've successfully downgraded my CAX30 tonight to the 1.4.11.2 firmware.  My 5 GHZ starting acting very strange in the past couple of weeks.  My neighbor has the same modem.  He called Netgear and they told him he had a "virus on his network".  Not a virus on a computer - but "on his network".  He went to Costco bought a new CAX30 since his was 6 months out of warranty.  All of his 5ghz connection problems went away.  I guess he did have "virus" on his network....it's called a bad firmware and Netgear trying to sell him their Network Guardian Software package......geez.....