Board Thread:Boruto: Naruto the Movie/@comment-26508646-20150902025453/@comment-734582-20150906202823

Ajr1218 wrote: I've said it before in a similar thread, but I just don't think the logic behind all these chakra modes' appearance has been thought through. I do strongly have the feeling that Kishimoto hadn't quite settled on a visual.

The source is the same: Kurama's chakra without his will imposed (which was what made it red). Minato attained the same, Yin-Kurama flooding his body with his actual chakra. Asura's case is unexplained, but the path of least inconsistency is that he was Kurama's jinchuriki.