This has me baffled, and brings me here to make my first post.
I had an issue with date filtering on an existing report using GA4 data, so I recreated a minimal version to test. The issue remains.
Strangely, if I set the date range to 2025-01-01 → 2025-11-30 I get much higher numbers than if I extend the range to 2025-12-31.
A sample can be viewed here.
Can anyone help me identify what might be causing this?