So i've been lingering around here and i have run into a problem which gives me the perfect opportunity to hide no more!

I discovered strange horizontal markings on my slides. You can discount lab errors as ive used vision imagelab in sydney quite a few times before and never had the problem (they use a refrema dip n dunk). The film in question is e100g but ive seen the same on e100vs. this only started after i started using a nikon FA that i recently bought, leaving my fe2 for black and white. Inspecting it under the microscope at 40x magnification with the shallow depth of field i can tell its on the base side of the film but whats even stranger is the markings can be rubbed off with soft lint free tissue and also it is an often occurring albeit intermittent marking on the rolls of film. also, under the microscope the line markings look very similar to fungal growth or a trail of miniature ice crystals... they run reasonably straight although they do look a bit like a seismometer line recording.

from this i can presume the FA is at fault, but how? its not a permanent marking (no scratch visible after i rub it away).
all i can deduce is that the camera needs cleaning or somehow 3 rolls (how much ive shot with it so far) have had some particle in the felt trap.

any thoughts or suggestions? or am i just smoking something...