[DataFormat.Error] when refreshing queries in Excel

I have a "master" excel file stored on a SharePoint site which has a number of queries fetching data from other Excel files stored in the same SharePoint folder.

Recently, when I pressed "Refresh All", I got an error message stating:

[DataFormat.Error] The input couldn't be recognized as a valid Excel document.

Immediately after clicking OK, the data seemed to update as expected. The owner of the source workbook was updating data and had autosave turned on when I went to refresh the queries.

I should also note that each "Source" file from which the data is updated have permissions set up such that only myself and one other individual can view/update the file on SharePoint.

Any ideas on what might have caused this error?