Why are Kobato's eyes inconsistent in color between episodes? In Boku wa Tomodachi ga Sukunai, Kobato (Kodaka's sister) appears to have Heterochromia iridum.
Her right eye is red and her left eye is blue.

But in episode 5 of the first season, both her eyes are blue.

What gives?
Is she wearing contacts? I wasn't able to find an explanation for this from the Anime.
It is not heterochromia. The manga does explain it better and ...


her normal eye color is blue.
she is wearing a contact lens. 


There is also a mention of her mother being English and having red eye color. So wearing a contact might be a fashion statement.