There should be an option to not cache credentials for data sources from connections with Power BI. This is a security issue and does not go well with customers.
Found a way to remove the cached credentials. In Power BI Desktop select File, Options and Settings and then Data Source Settings. Find the data source with the cached settings and use the "Clear Permissions" button to reset. Again, it should be obvious to the user when cached credentials are used and which cached credentials are used. Even in the Data Source Settings form we can't tell which credentials are used with each data source.
