Mechanics Protean's interaction with Toxic's accuracy

[MattBud]

What type of bug are you reporting? Mechanics

What is the bug?
Protean user transforming into Poison type misses Toxic against opponent using Fly.

Are you able to replicate it? If so, how?
I only tried it in Gen 7 OU when getting clips for a video. Greninja uses toxic against Landorus-T and is supposed to hit as it transforms into a Poison type. They always hit toxic even against a semi-invulnerable opponent. Bulbapedia supports this for the ability Libero and Protean.

Replay (Turn 11 is the toxic miss)

https://replay.pokemonshowdown.com/gen7ou-2171707589-spxqgn7rijl9k3l6hxft65x7fukttb5pw

 

[urkerab]

Current sim behaviour is that Protean needs to run after the code that checks for Protect failures but before the code that runs semi-invulnerability checks. Unfortunately the buggy Gen 7 Toxic sure-hit for the rest of the turn behaviour also needs to run before semi-invulnerability checks, so it currently runs at the same time that Protect failure checking would. But that means it's also before Protean...