Parrots are invisible when on shoulder

When I walk through a parrot to put it on my shoulder, it disappears off of the ground like normal, but when I click F5 to see it, it is not there on my shoulder. Same goes for if I try to get another one on the other shoulder. I have tested to see that they are there, walking through a third one does not cause it to disappear and go to my shoulder, and jumping causes them to reappear back on the ground.