Just checked again, but the neoprene seem to be fine, no thinning.
It's got the wider green (bamboo) tape in the crotch and the legs so I'm wondering if it's got something to do with that not sealing the stitches so well.
Very annoying. A perfectly good suit, near enough ruined by a few pin prick holes in the crotch. I'm going to have to try and repair it as it's no good as a winter suit in the north sea. Does any repair service offer seam sealing of any kind?