We are getting hit with exactly the same at a much greater scale. 260K in our case. Exactly the same issue.

When you create Gemini Flash Cache with a TTL of 1 or 3 hrs, it creates the cache and TTLs it correctly, but the billing system keeps charing the hourly rate for the cache making the charges grow exponentially.

We've seen charges go up since 9/19 even though we turned off all the services from that account.

Struggling to get the attention of folks at Google (ticket, account manager, sales engineer: no one responds)