As a commenter notes in the Reddit thread, if the player has more than one Pokemon for their Pokedex prior to obtaining it from Professor Oak, then the game will assume it has already been collected.

Dominik Bošnjak is a freelance writer from Croatia. He has been writing about games for as long as he can remember and is sure he began doing so professionally in 2010 or thereabouts. If he was forced ...

The Pokémon series has changed a lot over the years, and these in particular made the series better than ever.

After nine mainline generations of games, the full list of Pokémon has grown to include over 1,000 unique monsters to catch, tame, and battle. Each game follows roughly the same structure of building ...