Because the developers were still experimenting with Double Battles where the player teams up with an NPC ally to fight two NPC opponents, this lead to a glaring oversight during the battle where the player joins with Steven Stone to battle Maxi and Tabitha where, during the battle, Steven's Level 42 Metang can actually gain a substantial amount of EXP simultaneously with the player's own Pokémon. This essentially means that, with careful manipulation, the player can have the ally Metang get enough EXP to grow to Level 43. This so far is the only instance in the entire Pokémon main series where, in a non-scripted battle, an NPC's Pokémon can gain EXP and level up.