It's been a while since I've used an explore map , but does it show prey ? since the event monsters for this month seam to be a little bugged. They should up with prey but the enemy's counter goes up when they show up ( so they count as an enemy) , so if you skipped a herd of elephants but one the event things are with it, it will count as an enemy thus leaving a enemy . Like I said I haven't used a explore map in a while so this imput may be completely wrong xD and your problem may infact be a bug and restarting the level should fix it , if not I suggest making a bug report about it