Hello, I've encountered this bug a while back in 1.12.2 and had to wait until I got to 1.16.5 before reporting it (as I wasn't sure it was fixed) and here it is.
Z-Hypnosis and Z-Grass Whistle (didn't try more moves) never miss. I figured it is because Damaging Z-moves are supposed to never miss but it shouldn't be the case for status ones.
- Use an npc with a pokemon that can be put to sleep (care for their ability) and use a pokemon with Z-Hypnosis or Z-Grass Whistle and use it on turn one. After 10 to 15 battles you will have never missed even though these moves have 55% and 60% precision.Here are showdown battles to show that those two moves can miss (in National Dex 9G but it should work the same in 8G) :
- Hypnosis: https://replay.pokemonshowdown.com/gen9nationaldex-1889786540-zb8ohclv9mzbb9doc2909g9hfjc1x4lpw
- Grass Whistle: https://replay.pokemonshowdown.com/gen9nationaldex-1889789149-hmqm08npydscpoy6c2sv207fs44zjtzpw
Feel free to try some other status moves as well as I have stopped myself at those two.