The Crown Tundra DLC has given every Legendary Pokémon, as well as other classics like Dragonite and Metagross, many long time players naturally want to bring back their Pokémon from previous games. Thanks to Pokémon Home, players can transfer their old Pokémon into Sword & Shield from games of past generations. Unfortunately, a bug has emerged in the game which is causing some player's beloved Pokémon to be unusable online. That means the Pokémon can't be used in online battles or take part in online Max Raid Battles.
The source of the problem is a new item introduced in The Crown Tundra called the Ability Patch. This item is sold in the Max Lair and allows a Pokémon to activate its Hidden Ability, which is a secret secondary ability most Pokémon carry. More often than not, a Pokémon's Hidden Ability is better than its natural ability, sometimes by a very wide margin. The addition of the Ability Patch was seen as a huge news by almost all of the Pokémon community. There previously hadn't been a concrete means of activating a Pokémon's Hidden Ability. Normally, if a player wanted a Hidden Ability Pokémon, they would have to find a Max Den with spiraling purple light and get lucky. Outside of farming Dens though, there weren't any means for activating a Pokémon's Hidden Ability before the Ability Patch.
The item has the potential to completely change VGC play. Thanks to the Ability Patch, Pokémon that weren't viable competitively have a chance to be much more useful with their Hidden Ability activated. Many players have transferred Pokémon from previous games into Sword & Shield specifically to use the Ability Patch, except a few have run into a major issue. It seems that when a Pokémon is transferred in from a game in Generations three or four and given the Ability Patch, it will not be usable online. This is a serious problem that is causing players to essentially lose the Pokémon they've been holding onto for years.
Using The Ability Patch On Pokémon Transferred From Gens 3 & 4 Will Break Them
Pokémon from Gens three and four are the only ones affected by this Sword & Shield bug. This means any Pokémon from Ruby, Sapphire, Emerald, FireRed, LeafGreen, Pearl, Diamond, Platinum, Soul Silver, and Heart Gold are affected. Hidden Abilities weren't introduced into the Pokémon games until the fifth generation. Because these Pokémon are coming from games that didn't have Hidden Abilities, technically, they shouldn't have them either. Normally, when a Pokémon from these generations is transferred into Sword & Shield with its Hidden Ability, it's flagged as a hacked Pokémon because it shouldn't have a Hidden Ability at all. But now that any Pokémon can have a Hidden Ability thanks to the Ability Patch, the game can't tell the real from the fakes. It thinks the Pokémon with a Hidden Ability from the Ability Patch are actually hacked.
This is a serious problem that's afflicting many Pokémon fans. Rare and Legendary Pokémon players have been holding onto for over a decade are now unusable because of a glitch in the game. It must be devastating to go through all of the lengths to transfer a Pokémon from a Gen three or four title to Sword & Shield just for a new item to make it essentially useless. This bug shouldn't be a difficult fix for Game Freak. It's all a matter of resetting the Pokémon checker that filters out whatever's illegal online. It just depends on when Game Freak will actually get around to fixing the problem. The issue just recently came to attention, so if enough noise is made about the bug, Game Freak is certain to fix it.
Anyone who has already experienced issues with this bug is strongly encouraged to post about it on Nintendo's forum. Hopefully this problem is fixed sooner rather than later. Until then though, players should be extra careful with who they give an Ability Patch to while playing Pokémon Sword & Shield's Crown Tundra DLC.