'Magenta Ring' displayed every 10 minutes or so since 2.3.5.30 update

Running 1 RBR50 with v2.3.5.30 and 2 satellites. App is v2.4.5.17

- Wifi network within the house is fine, but the router drops its connection to the cable modem every 10 minutes or so

- Orbi App lists the Internet as 'offline' when it clearly isn't (router is displaying a magenta ring right now, app claims the internet is offline, and yet I can post this here via the same network - and yes, i've check what network I'm using :) ). I think the connection drops briefly - enough to cause a glitch in online gaming/prevent Alexa contacting amazon when the kids are using it, then Orbi gets stuck. I see a massive ping spike, and then it settles

If I check the cable modem logs (direct cable into the modem - it shows the router has been connected for hours

I have no idea what's going on 

Help?