I just got a Smeargle from photobombing my Leaf Tornado Victreebel, and it got Magnet Bomb?! What’s happening?
The new stat-affecting moves (Leaf Tornado, Acid Spray, and Power Up Punch) are available only to certain Pokémon, so Smeargle can’t learn them. It gets a randomly assigned move instead.
Smeargle is hard programmed with lists of fast moves and charge moves that it can copy. This is not an ideal way to code this because if the pokemon Smeargle photobombs has a move that is not on its list, then it gets a random move from the list instead. New moves and old deprecated moves (i.e.: Poliwhirl with Scald) are not on the list.
Hard programmed lists are also the reason for some other problems like the Celebi special research for evolving a second evolution grass pokemon not working with Gen4 evolutions (Grotle and Roselia). When they released the research, instead of programing it to watch for qualities of grass pokemon that are a middle stage, they just wrote a list of all currently available middle stage grass pokemon. When new grass pokemon are added, they have to remember to go back and edit this list.