Why is Rattata immune to Poison Powder in Pokémon Red?

Question

So I was battling Blue by Nugget Bridge and I was trying to use Poison Powder but it said that it was immune. Is it some kind of glitch because abilities weren't introduced until Gen 3 and it's a Normal type Pokemon.

Comments

Was Rattata having any other status condition?

Answer 1

There can be 2 reasons in my eyes, here they are -

1) In Gen 1 sometimes missing shows up as it doesn't affect the target Pokemon.
2) You already had a status condition.

These can be the only possibilities for this case.