I think the answer to this is that Google has pretty … communication and is shutting down this model. Lots of users have reported this on Gemini 2.0 Flash and the only solution has been to move to the 3.x series models.
It’s mind-bogglingly because 2.0 flash still is not supposed to be deprecated and they don’t have any actual replacements for its performance/latency but here we are. Basically they want people on models marked “preview” rather than production-stable tagged models.
Probably not the answer you’re hoping for but we’ve seen this behaviour with this exact model and Google has said nothing publicly. This is just based on what myself and many other users have experienced, unfortunately 