The effect with the border in the last panel was 100% a layering mistake I decided to keep.
Given that magic is involved, there are many possible explanations for why Magus wound up with differently colored clothing, up to and including it simply being a side effect of him wanting to have his true hair color instead of Elliot's.
Me? I like to think Magic's flair for the dramatic, be it intentional, unintentional, or somewhere inbetween for reasons beyond corporeal comprehension, lives on.