Overhang, I have exactly same problem!! And I am trying to isolate the cause. VTF is okay. Azimuth is okay. I did not think about 180 gr v/s regular 'thin' records. Come to think of it , in my case also it happens with heavier LPs. At first I thought, it is due distortion, or due to dirt and finally due to vibration. May be I will learn some thing too.
It is annoying as hell, perticularly after spending big bucks on the new set up!!