You create a gap in the target's memory, preventing the target from remembering anything that happens from the moment you cast this spell until the moment its complete duration ends. Fleeting memory doesn't wipe out its target's memories until the end of its duration, so the target can remember the preceding rounds until the spell's duration ends. If the spell ends prematurely, either because you dismiss it or because it is dispelled, it disperses without affecting its target's memory. Whether or not the target's save is successful, the target forgets that you cast a spell.
Home Previous: Fleeting Defect Next: Fleeting Memory, Mass