Did you ever get resolution?
I have similar errors on my CM700, same hardware/firmware versions. I'm in a detached single-family residence with an overhead cable drop. No other devices, not even the set-top box for TV. The chat person just "reset the firewall" on my modem...but hasn't shown up on the event log. I was then told to contact the manufacturer, which of course directs back to Xfinity.
What do the modem's signal stats look like ? Try getting them here http://192.168.100.1 or here http://10.0.0.1
Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.
What is the exact make and model number of the modem ?