Bugged Siren set?
 

Okay, I never noticed this in the past, so I'm wondering if it happened somehow with the new avatar setup, but the hair on the siren set goes in front of the skirt no matter where I put it in the layering. That can't be right, can it?

It looks right to me, but I do see that the particular way the items are split up into layers can look a little bit misleading. The "above" layers won't have any visible effect if you switch them because the head hair doesn't overlap the top, and the "below" layers can switch whether the hair or the skirt is in front behind the legs. But the parts of the top that hang down by the avatar's thighs are on the "above" layer, so you can't layer the hair in front of that.