Power bi billing increase

Dear Fabric Community Support,

I'm writing to report a significant and unexplained increase in our Power BI on Fabric billing over the last month. Our usage has been consistent, but our costs have not.

We have a setup with three similar workspaces (just very little differences in used filters), each containing a direct query summary report. These reports are connected to our classical reports that are refreshed once per day with import query. They do not perform any data transformations or use large, complex queries. We have not made any changes to either the classical or the direct query summary setups.

Despite this, we saw the billing for these direct query summary reports increase up to five times the previous month's cost in two of the three workspaces. The third workspace, which is identical in setup, was not affected. As a troubleshooting step, we also tried caching the queries, but this did not help.

Our internal support team suggested the cost increase was due to a surge in usage, but this contradicts our findings. We expected a direct query to only execute and incur costs when someone actively opens or interacts with the report. However, on a day when nobody opened the report at all (e.g., a weekend), the cost for that specific summary report was about 20e even though last month it was almost free.

Is there anything else we can try to diagnose or mitigate this problem? Has anyone in the community experienced a similar issue with unexpected costs from direct query reports on Fabric? Any guidance would be greatly appreciated.