User blog comment:ChishioKunrin/"No Scar" Moments in the White Trailer/@comment-25555436-20150103001449

...So...what. I thought everyone in the fandom had already discussed about these moments where the scar is "not-there". But oh well, I'll give my 2 cents...again.

It could have been animation mistakes. It was done in a time where Monty and co. didn't have too much experience with Poser, mistakes are possible.

At least, that's the only explanation I could think of, other than Weiss's Aura being a bit Mood Swingy and being unable to decide whether to heal that scar or leave it there. Otherwise, doesn't make much sense.