We recently switched to Vodafone, and have an Ultra Hub on an unlimited fibre plan.
Every now and then, the 2.4GHz wifi band disappears - no devices in our house can see it, even though the Modem's web interface says it is live. The 5GHz band stays visible the whole time. It's highly frustrating and has no apparent cause. Upon rebooting the router it usually comes back, drops again, and then eventually comes back.
Any ideas? FIrmware version is 17.1.7875-2461002-CRF731, can't see any obvious method to poll for an update from the router settings.