RBR850 Offline Every24hrs

Hello, hope someone can help. I have an Orbi RBR850 which has been working flawlessly for over a year now. We also have two satellites in the house, but they are not the source of the issue. For the past few months the router goes offline every 24hrs. This only way to get it to reconnect to our Xfinity (Comcast) modem is to either reset it or disconnect power and reconnect. It reconnects every time without issue and operates normally for 24hrs. When I indicate 24hrs, I mean exactly that. I can change the time of day it goes offline by doing either a reset or power down/up preemptively while it is still operating normally. I have taken now to do this preemptive reboot right before bed. Previoulsy it was going offline during the middle of the day, frequently interupting online meetings. So overall it has become managable, but still a pain to have to reboot every single day. 

This all started a few months ago. There were no changes made to the Xfinity modem, our Xfinity service or the Orbi system. When this started I originally thought the root cause was the Xfinity modem. We had a power outage for a few days and the issue seems to have started near the same time as when the power was restored to our area. I have heard the Xfinity routers are quie sensitive to power spikes, so we have them out to repace the modem. Even with the new modem there is no change in the behavior of the Orbi. I have checked and the Orbi is running the latest firmware. 

Any help or ideas would be appreciated. 

Thanks.