Hello!
This is not a bug - but rather seems to be a mistake in the retrofitting process regarding the new 'Punk Collar' decor on the adolescent male pose.



Looking to the start of the chain on the left, you can see it just sort of cuts off. I believe it was meant to be erased just a little more to give the effect of it tucking away under a tuft of fur. ^^ I was originally going to PM Xylax with this screenshot, considering it isn't technically a bug, but figured he probably has enough to deal with as-is, and this is a tiny mistake.