The tag interracial gets stuck on any image involving sex between people with noticeably different skin tones. This is a problem because East Asian populations have a considerable degree of variance in skin tone. Moreover, East Asian cultures ascribe a certain meaning to skin tone that Western cultures typically do not: pale skin is associated with high class, since it is historically correlated with being indoors and out of the sun. Skin tone differences are thus often exaggerated in certain kinds of hentai even when both partners are supposed to be native, ethnic Japanese.
This is confusion is understandable, as ambiguities in art styles can even make it impossible to tell what the artist intended from the image alone. Per the "tag what you see" rule, I'd suggest replacing the interracial tag with something like skin color difference, which is impossible to get wrong. I hesitate to request an alias because of the possibility of that tag being applied to a few images with (e.g.) an Asian and a European whose skin tones happen to be the same. After making the change, we could possible reintroduce the interracial tag with stricter guidelines for its use, but given the current epidemic of wikiphobia I'm not sure that would be a good idea.