That’s not necessarily true. The TV signal and the internet signal, while being carried through the same cable, operate at different frequencies than one another. So it is entirely possible that a cable is partially damaged somewhere either at a node or underground, and the OP is still getting an internet signal but not a “strong” enough cable signal.
I had a similar issue not too long ago where an underground cable was damaged up the street from me and I would get some, but not all cable channels (and most of those where plagued with fuzz and ghosting) and my internet would work intermittently. My phone however, was completely dead.
It turned out that they needed to bore under a neighbor’s driveway up the street to run a new length of cable, and in doing so, the cable company’s contractor struck and damaged our street’s water main, which was also under this guy’s driveway. So then they had to fix the water main ASAP and they had to tear up the first third of the guy’s concrete driveway to do so.
The neighbor was really upset about all that. They finally got everything in working order (and replaced dude’s driveway, but it doesn’t look the same as the new section looks “newer” than the rest) but I was partially down for a couple weeks before they found, diagnosed and repaired the issue, because I am the only customer on my side of the street that has cable…the neighbor with the driveway lives on the other side of the street. All of that trouble for little old me.