Thank you Sam. But see, that's the thing, the data is just not refreshing. I have a controlled set of test data and last week I did some small alterations to test the data refresh. So far, nothing has changed in the reports since the moment the PBIX was uploaded - even though the embedded visuals say that the data has been refreshed today.
Same tests on the same PBIX uploaded to powerbi.com, the data refreshes perfectly.
Are there any tools to troubleshoot the embedded data connection, and see where it's failing to update? I just don't know where to look at.