Naming of Pathfinder functions is inconsistent between the Pathfinder Panel (and the Undo text) and the Pathfinder Effect.

The Tooltip shows “Unite” in the Pathfinder Panel
Unite from the Pathfinder Panel is the same as Add.
Unite is missing from the Pathfinder Effect and is named Add instead.
If you have clicked the Unite button in the Pathfinder Panel, the Undo option displays “Undo Add”.

The Tooltip shows “Minus Front” in the Pathfinder Panel
Minus Front from the Pathfinder Panel is the same as Subtract.
Minus Front is missing in the Pathfinder Effect and is named Subtract instead.
If you have clicked the Minus Front button in the Pathfinder Panel, the Undo option displays “Undo Subtract”.

The easiest way to solve this is to change the tooltips in the Pathfinder panel for Unite to Add and for Minus Front to Subtract