Given that it is only affecting lower frequencies, this could be a very narrow frequency source. Talking about the cable run, the Claymore restaurant might be near where the cable goes, I am not sure where it crosses the main road from the north to south side if it is not on the south side all the way, which it might very well be.
I don’t understand how there can be much difference in the placement of the newer line compared to the previous ones as they are all heading back from the same place to the one and only exchange.
It is very weird that it is not seen on the other line.