Hey jimbob82,
Thank you for reaching out! The Arris SBG shouldn't require rebooting for the 2.4G network to work. It is possible the modem is faulty or it is a settings issue. If you haven't done so already, I'd recommend trying a pinhole reset with the steps here to set the modem in factory settings. Then monitor to see if the 2.4G network stops broadcasting at any point. If it continues to do so, your best bet is to touch base with technical support for more troubleshooting or arrange a modem swap. Keep me posted.
Cheers,
Tony | Community Mod.