Anakin’s never been the most sensible guy. FACPOV suggests it’s quite painful for force ghosts to separate themselves from the Force, so maybe they can only manage to do it a limited amount, and perhaps every time Anakin manifests he gets distracted talking about that time he fought the Zillo Beast, or that time Obi-Wan faked his death to Face/Off a criminal, or that time he beat up Rush Clovis for hitting on Luke’s mum… Or maybe ghost Anakin just finds it difficult to talk about the twenty years he spent as a Sith. (I’m not seriously suggesting any of this is an actual justification for the plot hole.)