I assume the crackdown on players waving imaginary cards (that never seems to actually be applied) also goes for managers too, hence the booking.
The refs are nothing but consistent in their inconsistency.
It was on the hour mark, straight after Caicedo had been booked I think, and he was waving an imaginary yellow card at the West Stand and throwing his arms up, which isn't surprising seeing what happened at the end of the first half.