So I was playing on survival recently, and I tried to sleep in an area after lighting up all nearby caves. But the game told me I couldn't sleep as there were monsters nearby. I swapped to peaceful mode, and the same message even though it was peaceful, and no hostile mobs were loaded. And after a little more of searching, I tried to move my tamed parrots who were imitating monster sounds to a further area and tried sleeping, and I was actually able to sleep that time.