Values differ depending on filter time range


I’m new to Grafana/Loki and trying to figure out how it all works.

I have this pretty simple Query towards my Loki datasource:

sum(sum_over_time({Kind="Report_AggHour"}[1h] | logfmt | unwrap NumberOfReports))

And what I can’t figure out is why, depending on my time filter the value differs.
For example if i filter 10-22: The value at 21 hours is 2737
If i filter 20-22 the same value is 7392.

And if i look directly at each row in the Explore view and count it. The second number is correct.

Values are stored hourly with a timestamp of for example:
2021-10-05T18:00:00.000Z & 2021-10-05T19:00:00.000Z

Can anyone point me in the direction of why this is? Doesn’t all values get counted when I look at a larger data set?