Why does Steven's Metang gain EXP?

Question

When you fight Maxie in the Mossdeep Space Center the EXP also goes to Steven's Metang. Is this a glitch?

Answer 1

Actually, this isn't a glitch. This is the only Multi-Battle where defeating an enemy Pokémon grants you and the AI EXP.
Source: https://m.bulbapedia.bulbagarden.net/wiki/Multi_Battle

Comments

It may not be a glitch but is definitely a Developer oversight. :P

Answer 2

I don't think it's a glitch, I believe it's the first in-game multibattle in the whole series and was most likely a developer oversight, heck it is possible for Steven's Metang to level up.
However this occurence if I recall doesn't happen with the games that came afterwards, an example was the battle against Lance and Clair in the Dragon's Den with your rival.