It looks to me as though the die has suffered some degree of filling on the top cross bar on the E and the P as the central cross part on both letters is doubled , and that then an E and P have been re-punched slightly out of position over what was left of the old letters. Below is an example of a coin with the G in REG having partly filled and then re-punched incorrectly lower and well out of position , and still leaving the outline of the old G. Over stamps don't seem uncommon on early bronze coins , but if its a different letter or the same letter inverted or rotated through 90 deg , then it becomes much more collectable.