NTE5C - Faulty?

Been noticing random noise bursts of no particularly trend or frequency on my line since taking up the faster 80/20Mb service.

DLM has been attempting to reduce my SNR to 3db and failing for a couple of months now due to these random noise bursts which causes ES's to go through the roof. I thought my old HG612 was on it's way out so replaced it with a Zyxel VMG1312B.

Last Saturday I watched as my line dropped sync 4 times in 10 minutes but re-syncd at around 71/20 every time. The DS SNR was initially 5db but then was down at 1.8db for a short time while the ES count ramped up.

Since removing the faceplate and plugging in to the test socket, the line has been stable and DLM has continued to reduce the SNR to 4db and is now syncing at 74743/20000 - ES's are low.

Do these NTE 5C's develop faults?