you probably have a signal level or noise issue. There cannot be any open splitter ports,loose connections, coax off to nothing, corrosion, etc.
Please describe how many devices and splitters from outside to the DTA and modem:
If the video feed is "stalling" (freezing like if you had paused it), that's what happens when a connector is either loose or there's damage causing it to be partially connected. It's not usually ingress, but rather a loss of signal (or just really low signal, I mean like -20 dBmV low).
If I were to barely have a coax connector connected and just kept touching the center conductor and then unscrewing slightly to break connection, I could perfectly replicate what you are describing.
Worse, if it is actually barely connected somewhere like that, that causes TREMENDOUS ingress for you and your neighbors (won't affect TV that much, but will definitely affect internet and phone).
This is a legitimate TC (troublecall, a repair on-site) issue from what you've described.
Bear in mind this isn't going to be just a simple "replace/swap DTA" (the symptoms you've just described are almost never the DTA box itself), but rather a full-on investigation. Schedule accordingly (and not where you have to leave to go to something in an hour).
I'd recommend starting by seeing if it's something as simple as a loose connector (including checking the wallplate). Knowing where your service comes into the home and path that your wiring takes to getting it's way to the DTA is important, and potentially a time-saver for you to have that knowledge about your home.
DTA's cannot tell TWC/Charter support remotely what the signal levels are, only boxes with modems with them (or just simply internet/phone modems) can do that. That is why I'd recommend on-site help from one of our hourly Field Technicians. You can help yourself and the field tech out (and make the appointment go quicker) by making your coax outlets in the home accessible (i.e.: if they are behind furniture) in advance of your appointment and troubleshooting a bit peer-to-peer in this forum. But my professional recommendation is go ahead get something scheduled.