Some horses are just strange. We have one boarder who will not pee in his stall, and poops on the windowsill. Another poops on the wall (I don’t know how she gets it to stick there). One possible solution for the feed tub is to remove it after each meal, so it isn’t there for him. No idea how to resolve the water bucket. I just used to have to clean mine daily.
It is never the horse's fault