I keep getting critical errors and more frequently resulting in loss of all 'out the door' connectivity for about a 3 seconds or so, but it's long enough to interrupt comms to my assets. A good example is my Klipsch sound system that uses play-fi (via wifi) loses comms at the exact same time as my work VPN drops, so i know it's not an internal network (my LAN/WiFi) at this point. My LAN/WiFi devices still stay connected to each other when 'out the door' comms drops out.
My equipment is a Network C6250 Modem/Router/WAP combo.
The issues i'm experiencing seemed to have started a couple months ago but gradually worsened to the point of unusable.
I tried to paste my C6250 event log entries here but it won't let me paste anything in the body of this form, but rather only the 'subject' line. I recall reviewing this forum and seeing someone else with the same problem and an xfinity rep reached out to the guy who made the post and had him Private Message the xfinity guy --i'm not sure if the issue was resolved.
You could try screen shooting them and hosting them at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to it here.