The reports have an intentional behavior of being stitched and cached. This is important as it ensures two things,
That data isn't constantly changing for merchants who are refreshing the page. Useful for cross-referencing and performing math checks.
Our reporting does a pretty intense process where it goes through each line Item for every order and it's associated relationship with a widget plus some other stuff. As such, we needed to make sure that reports with 60,000 orders a report weren't blasting our servers every time the page gets refreshed.
The process of clearing the cache has the purpose of refreshing the report with all of the relevant new data. This happens automatically from time to time. However, if you are checking the reports often it'll not refresh because it thinks that you, the user, want to see the cached report and not the most up-to-date one. In those instances, you'll want to bust said cache. (refresh it)
To perform this action, navigate to Rebuy Admin > Reports > Clear Report Cache