Seeing several modem warnings and notice errors resulting in intermittent streaming video lagging, video distortion, etc.

This may or may not be the root cause of the problem (YMMV), but it should be addressed regardless. 

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the unbonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/reconfigured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also, check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, or animal chews.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

Good luck with it !

Hi there, user_q10i5u! Thanks for knocking on our XFINITY Community door with your connectivity concerns. I understand how important it is to have a stable connection when streaming your favorite videos. We’re really sorry if that hasn’t been your experience, that’s not the kind of journey we ever want you to have with us. Rest assured, XFINITY is here to save the day! Before proceeding with troubleshooting, I would like to ask what steps have you taken towards troubleshooting your connection so far?

@user_q10i5u 

Have you had a chance to see if any of those tips apply ? 

@user_q10i5u 

Thanks for replying ! Ok, so if there is nothing more that can be done to improve the connection quality, then yes, you'll need a tech visit as you stated. 

Bear in mind that if the premises-facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.

Good luck !