This may occur after elements which were generated on the model are then deleted and Revit must recreate the Energy Model to update. The Surface has changed while Revit is using the older version of the Energy Model. You may see a message in Revit that the ‘Referenced Object is not valid’.
If the Refresh button is used and then the Building Manager is opened again and the Solar Loads are recalculated, the current condition should update. If this does not have an effect, close the application and reopen, a new Energy Model will be created and the current Surface condition will be identified.