I think AS was deliberately doing that and appears based on some extreme settings as jrabbit said may just show seams. I have only used native and all are shader domains...not layers lists, but no seams unless I really alter the domains. The gradient usage there definitely seems key. Cause if you alter a domain, of course, it would look different and not blend naturally. Haven't really seen this with same reasonable settings tho.One thing is sure...the SSS is pretty complex and amazing tho.

No need to think outside the box....
    Just make it invisible.