On DirecTV, I see a technical difficulties notice — after I typed that, "local" adverts inserted by DirecTV appeared. Earlier, my receiver cued LF over the technical difficulties notice! o_O
After I posted this, the TWC feed returned with no audio.
Now the notice has returned.
It just cued LF over the notice again.
This appears to affect only TWC — I checked a few other channels and I saw nothing wrong there.