I was attempting to catch a shed skin arbok, which is quite difficullt when you can't parlyze it. So I used worry seed on it to make its ability insomnia and then paralyze it and catch it. However, upon inspecting it in my pc it still has the insomnia ability. I assume this is a bug and could be really unfortunate if it works for other pokemon as well. Although I doubt many people will be using worry seed to catch a pokemon, lol.

just relog and everything will be alright

Yeah i've relogged quite a few times over the past past couple days. Still have an insomnia arbok

lol thats op if you could do it with other pokemons