Anonymous,
My issue is with excel data models. I have a number of Workbooks published to the PowerBI service which the service refreshes. This has worked fine for several years and means my data remains up to date.
As of approximately a week ago the service has started to corrupt the data model within the workbooks after the refresh. This has affected various workbooks, and since this is not specific to one workbook and these workbooks have worked perfectly well for several years I deduce the issue is caused by the service and likely is affecting others as well.
To replicate the issue I suggest creating a workbook with a Power Query table, loading the table into the model in power pivot and publishing it to the service. Next refresh via the service, then open the workbook on your PC and try to open the model either in Power Query or Power Pivot. I find after these steps excel will crash without any error due to the model being corrupt.