In the episode of Forever Plaid:

When London and Maddie are in the cafeteria in the morning of London's first day, London has a kind of teal flowery purse with one chain strap. But when London and Maddie are in detention with Zeke, and the nun leaves to get some ingredients for sugar cookies, London gets up and tries to leave. She has the same purse with the chain strap when she gets up, but when Maddie tries to stop her, the purse turns into a shiny teal purse (with two solid teal straps)when the camera changes to London. But when London walks out the door to "go to a fashion show", her purse is back to the original purse.