When the transaction is acknowledged by the provider and the status never changes from undefined, AdyenV2 is requiring a pspReference to cancel the transaction. This isn't an expected behavior because this field doesn't exist in the PPP, thus the customer gets stuck on the PIX modal at the checkout UI.

Start a new transaction with PIX using AdyenV2 and don't finalize the payment on the app. Then, the transaction will get stuck in this status.

There's no workaround.