It could be a faulty port on the MSAN/DSLAM, which a frames engineer would be the 1 to fix it. The fact the line was previously used should make no difference though.
I would be asking the ISP to request the frames engineer connect the 2nd line to the same MSAN as the 1st line, providing there's capacity. Failing that a pair swap. For the Hlog and line attenuation the 2nd line should be much closer to the 1st line.