When I play Yellow it and I am facing a trainer sometimes when they use things like Growl or Leer they fail. Why is that? But so far my Pokemon have not had that problem.
Don't Forget Gen.1 was extremely glitchy and had quite a few bugs in it's system. But since you say it is a PlaR,It's most likely a bug in the program.
There is a special AI handler for status moves that causes these to miss 64/256 of the time.
This is not a bug, it's just some AI weirdness.