Yaknow, Jim, I think the problem is the automatted test equipment. it tests and records the line every night, so it establishes a baseline. then, you get something that takes a few weeks to get in there, and it slowly moves the baseline. Then, finally, it starts effecting things, but the test gear says everything is okey-dokey... 8-)
It is only when you have someone actually MANUALLY take a look at the line that he notices the tip ground... 8-)
Charlie