While developing a report in a dev environment, a slicer value is selected. Upon completing the report the report is promoted to a QA environment and published into PBI Service where the data set is refreshed. Upon opening the report the slicer still shows the value that was selected in the development environment, a value that does not exist in the current dataset.
The impact from this issue is that the user will see an empty report since the selected value doesn't exist. Not a great first impression ;-).
The obvious solution/workaround (manual) is to clear all slicers before promoting or publishing. However, a better solution would be for the PBI Service to validate slicer values whenever the data set is refreshed and clear them, or have a setting to enable clearing them if that is the desired behavior. Going one step further, it would be best to allow some logic to dynamically select a slicer value for that initial presentation, e.g. set the first value found as selected, i.e. instead of starting with 'All' values selected, which can be similarly meaningless, enable just one value to be selected.