Odd problem with TT setup...

I’ve got an SME 30/2 TT with the Gold V tonearm. Recently, I’ve noticed on a few albums with particularly punchy kick drum passages (The Police Zenyatta, Talking Heads Slippery People particularly) that on occasion I hear a distinct “pop” as if overdriven during these notes. But not every time in the song, nor on every song.. The odd thing is, it doesn’t matter what I change... my typical cart is an Atlas, but it has also done it with other carts, namely a Sumiko Blue #2 MM. Capacitance settings don’t change the problem, I’ve tried cable swaps on both ends, different phono stages, gain settings, loads etc. it happens in any channel on my Hegel regardless of volume, it happens if I run straight into my head phone amp with headphones. The ONLY constant here is the tonearm. All of the setup parameters are spot on, I’ve tried a variety of VTA settings, antiskate you name it. Is it possible the internal wiring of the tonearm can have a problem? Overall the sound is excellent, great soundstage, overall presentation etc. with the exception of this one issue. Any ideas?
So, the SME is off to be rebuilt and rewired. I’m sure it will be weeks before I see it. I suppose, if it comes back and I still have issues, we can start this thread up again! Crossed fingers!
@geof3  How did this work out?
Ah, kind of forgot about this thread. All sorted, and sounding great. Still have no idea what the problem was, but it is no longer an issue. I was having some other issues that just boiled down to getting the setup just right. Happy ending!