At my wit's end over intermittent connectivity issues and keep getting told there isn't a problem

Welcome to our community forum, @mrnelson03! I work from home so I know how stressful internet issues can be. We'll definitely stick with you here until we get to the bottom of this and you can enjoy your reliable connection. I checked your modem logs and everything looks great for the last 2 days. Since you're still noticing issues after multiple appointments with our technicians, I'd like to investigate the account in more detail.

Please send a direct message by clicking the chat icon in the upper right corner of the page, click on the pen and paper icon, then enter “Xfinity Support” in the “To” section. Please include your name and address and I'll be happy to help :).

1/1/1970 -- that's a time not established and a default time stamp when it's got nothing else.

Signal power is all over the map and is NOT OK.  They need to come back and take a look at it again.

I started the chat as @XfinityEmilyB instructed and am awaiting a response. I don't know what logs show everything good for the last 2 days though. We lost internet twice last night in one movie. 

Can someone explain Channel ID 32 and 33 to me? I just looked at it and channel 32 is up to 3.38 million uncorrectables.

ID 32 listed as "Other".  OFDM channel.  A phase lock loop channel of sorts to track signal.  Correctable errors are part of the protocol and cost you nothing.  Expect a lot of correctable errors on that as it fixes "jitter" or signal drift.  Uncorrectable errors on that are not good.

ID 33 just isn't locked at all.  So that one is error'd out at that particular time and is going down the error path of trying to reconnect.

ok, so both are definite problems. I have connected directly to the modem and had to reset the modem in order to get a valid IP and now ID 33 isn't even showing and all the uncorrectables are cleared. The log seems to have retained some messages but cleared a lot of them. I'm guessing it only retains the most important messages. The downstream channels are all mostly between 5.5 and 10.1 dBmV with SNRs being around 40-43dB. The upstreams all have a Power of 34-36 dBmV.

So direct connection to the modem and a reboot. Everything looked good remotely, so they are sending another tech out. I am really curious about this channel 32 "Other" which in 20 minutes since the reboot has over 12,000 uncorrectables. That's not normal, right?

One last interesting tidbit. When I reconnected my router and went to look at the modem again, the channels above 32 came back, to include that weird channel 33 that wasn't locked in my original post. Directly connected to the modem I get channels 1-32. Connected to the modem through the router, I get channels 17-45. 

The channel numbers are going to change with every reboot and sometimes just on their own anyway, but yeah, the uncorrectables are not good.  Also that big delta on signal power is pretty wonky and indicates a reflection in transmission line theory, and you are running out of spec anyway.  In your case, it's even stranger just because you usually see a pretty clear, predictable frequency dependency either increasing or decreasing as the frequency increases or decreases, but there's some strange poles in that shape.  Bad filters?  Malfunctioning amp somewhere?  Dunno.

None of this is helping you.  There's some guidance on what you should be seeing for signals here:  https://forums.xfinity.com/conversations/your-home-network/internet-troubleshooting-tips/602dae4ac5375f08cde52ea0 

I don't know what your gear would hold for logs on a warm boot.  None of the signal information on most gateways, and probably not much for logging on a warm boot.  Likely nothing on a hard power cycle.