Well as gar187er
pointed out, the frequencies in the other thread were LTE band, so your issue is likely different (and hopefully less troublesome and drawn out). I didn't want to scare you, just wanted to give you a heads up that sometimes these kinds of issues are difficult to track down.
I had a similar issue to yours, but it was on my upstream channel (this was before DOCSIS 3.0 so I had only one upstream channel). Periodically, it would just drop off and lose sync. It took a tech sitting at the tap with a meter watching it for hours before he caught the problem and this was after 2 truck rolls and someone in business class escalations getting involved!
I hope your issue is more cut and dry, chances are it is.