The experience of having a
significant epiphany about one's life only to
immediately forget it.
A conflation of the words epiphany + amnesia.
Origins
epiphany: Middle English epiphanie, from Anglo-French, from Late Latin epiphania, from Late Greek, plural, probably alteration of Greek epiphaneia appearance, manifestation.
amnesia: New Latin, from Greek amnēsia
forgetfulness, alteration of amnēstia