The Drilldown button is not located in the correct cell
This is an issue with Excel when you use the Zoom feature and the Zoom Percentage in not a multiple of 5.
Set the Zoom Percentage to a multiple of 5.
You may not be able to use the Excel Zoom slider to accomplish this. When using the slider, it is possible to select a value that may be reported by Excel as 75%, but is actually slightly different (for example 75.3%). To set the Zoom Percentage exactly, you will need to use View, Zoom from the Excel Ribbon.