Motorola MB7621 having intermittent connection issues; getting T3 time-outs and little help from Xfinity CS

I have a Motorola MB7621 modem that has been having intermittent connection issues for the past couple weeks. I've been getting T3 time-outs, and when I ask for help on this from Xfinity technical support, they are unhelpful. Yesterday when I called, I told the representative that when I logged into my modem, it said I've been getting T3 time-outs, and she replied, "what do you mean that you logged in to your modem?" A couple weeks ago after repeatedly contacting Xfinity and resetting my modem, which would only temporarily fix the problem, the agent finally scheduled a technician. Then the day before the technician was scheduled, I received a call from Xfinity "Advanced Technical Support Team" who told me that they found the problem and fixed it. I asked the agent what the problem was, and she would not answer my question in any specificity. However, my connection was much better upon receiving the phone call, so I didn't pursue it.

However, 9 days later (yesterday), the problem recurred. This time, when I called Xfinity, they could not detect any signal from my modem, so they again scheduled a technician. I asked them what they did previously that fixed it, and no one could answer my question. I ended up doing a factory reset later on yesterday that restored my connection. Since my problem is intermittent, I'm concerned that the technician will not be able to diagnose the cause of the problem. Do you have any advice? I've copied my modem logs below, though before I did the factory reset, there was an event from yesterday noting that my modem had reset itself. However, that event disappeared after the factory reset. also, I've had multiple T3 time-outs (that I've seen with different dates) but only one appears in the log. The timing synchronization failure might be from a few months ago when there was a local outage.

I'd appreciate any insight you may have. thanks! 

Downstream Bonded Channels

Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected 1 Locked QAM256 13 507.0 1.8 37.1 619 1844 2 Locked QAM256 21 555.0 2.1 41.8 0 0 3 Locked QAM256 22 561.0 1.9 41.9 0 0 4 Locked QAM256 23 567.0 2.0 42.0 0 0 5 Locked QAM256 24 573.0 2.5 42.2 0 0 6 Locked QAM256 1 435.0 1.2 41.5 0 0 7 Locked QAM256 2 441.0 1.2 41.3 0 0 8 Locked QAM256 3 447.0 1.7 41.7 0 0 9 Locked QAM256 4 453.0 2.0 41.9 0 0 10 Locked QAM256 5 459.0 1.8 41.7 0 0 11 Locked QAM256 6 465.0 1.5 41.5 0 0 12 Locked QAM256 7 471.0 1.7 41.3 0 0 13 Locked QAM256 8 477.0 1.9 41.8 0 0 14 Locked QAM256 9 483.0 1.6 41.5 0 0 15 Locked QAM256 10 489.0 1.4 41.4 0 0 16 Locked QAM256 11 495.0 1.5 41.5 0 0 17 Locked QAM256 12 501.0 2.0 43.1 0 0 18 Locked QAM256 14 513.0 1.4 43.0 0 0 19 Locked QAM256 15 519.0 1.7 42.9 0 0 20 Locked QAM256 16 525.0 2.1 43.1 0 0 21 Locked QAM256 17 531.0 2.0 43.2 0 0 22 Locked QAM256 18 537.0 1.4 43.0 0 0 23 Locked QAM256 19 543.0 1.7 43.0 0 0 24 Locked QAM256 20 549.0 2.4 43.3 0 0 Total             619 1844

Upstream Bonded Channels

Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV) 1 Locked ATDMA 13 5120 35.6 40.1 2 Locked ATDMA 10 5120 16.4 40.2 3 Locked ATDMA 11 5120 22.8 40.1 4 Locked ATDMA 12 5120 29.2 40.2 5 Locked ATDMA 14 2560 40.4 38.7 6 Not Locked Unknown 0 0 0 0.0 7 Not Locked Unknown 0 0 0 0.0 8 Not Locked Unknown 0 0 0 0.0