I've noticed an issue with Spite while battling Spirit Porygon2's. I modified the external JSON files to change Spirit Porygon2 to a pure Ghost type and gave it access to Spite as a random move. Every time one would use Spite, the move would not deduct 4 PP from the last move used, instead doing nothing. I had been using Darkrai while battling and used Psychic to ensure that I do not kill them. Every time one of the Spirit Porygon2's used Spite, Darkrai's Psychic did not lose additional PP.
While I do mention Spirit Porygon2 a lot in my tests, this is not limited to just him. Anyone with Spite is affected. I later did the same thing with Zoroark as part of a Trainer battle, and the same outcome occurred.