[Bug] Permanent Mega Evolution

[TheDrOfDoctoring]

It is possible to permanently mega evolve under certain conditions. In my case, I've found this to be possible using the Radical Cobblemon Trainers mod, but I think the steps can be followed through similar means.

1. Equip mega-ite on pokemon
2. (Possibly not necessary) Mega evolve the pokemon outside of the battle
3. Start a battle
4. Activate mega-evolution and use the move
5. As the mega evolution is happening, kill the trainer (in the case of RCT) / exit the battle unexpectedly. Do this before the transition finalises
6. If the final trigger for the mega evolution happens after the battle has ended, the pokemon should now be permanently mega evolved.

You can now remove the mega-ite from the pokemon, relog, etc, and the pokemon will persist in its mega evolved form, including all the ability and stat changes. Seemingly, the only way to revert this is to mega evolve in battle again.

Relevant Versions:
NeoForge 21.1.219
MC 1.21.1
Cobblemon 1.7.3
Mega Showdown 1.6.12+1.7.3
Optional(?): Radical Cobblemon Trainers: 0.17.6-beta

[yajatkaul]

I believe on rejoin it should turn back?

[TheDrOfDoctoring]

In my testing it doesn't appear to, for example after doing this for Charizard Y, which is the only one that has the drought ability. After relog, it will still appear as Charizard Y, and if you check the information it will still have drought, and entering a battle will trigger drought's effect.

[vaniron]

Happened to me on version 1.7.4 with pokemon having this data, now on 1.8.2 is no longer getting bugged but reset command doesnt help to fix already corrupted pokemons.