Without trying, I can think of five webcomics authors who changed their pronouns long after they started posting: Dana Simpson (Ozy and Millie), Joey Alison Sayers (Thingpart and now Alley Oop), Allison Shabet (Deadwinter), Elli Stephens (Goblins), and now Maelyn Dean (Real Life).
Is there something in the ink?
(See also.)
LATER: add Jodie Troutman (Sporkman), Jackie Lesnick (Girly, Cutewendy), Daisy Finch McGuire (Gastrophobia), Jeanne Thornton (The Man Who Hates Fun); and, the other way, Nate Stevenson (Nimona).