Issues with Google AI Studio

Hi, I have a website already published on ai.studio and working. When I try to publish a new version, Google AI Studio asks me to set up Google Cloud Billing. I’ve always used everything for free and I’ve been working on this project for two days without any issues. I don’t have two apps published and my Firebase project is on the free Spark plan. I’d like to know: Why am I being asked for Google Cloud Billing? Thanks.