Cobalion's follow-up effect not fully working

Hey, the card I'm talking about, Cobalion [Silver Tempest 126/195], is not doing what it's supposed to. The attack, Follow-up, is attacking okay, but the effect is being more trouble than it's worth. Here is the effect it says on the card:

Choose up to 2 of your Benched Pokémon. For each of those Pokémon, search your deck for a basic Energy card and attach it to that Pokémon. Then, shuffle your deck.

I'm able to choose the two Benched Pokémon I want to place energy cards on, but for some reason, it's not letting me place the energy cards onto them. When the selection screen appears, it shows the energy cards, but not the pokemon, along with saying something along the lines of pick 0 cards to put onto the pokemon.

Is it a bug, or am I missing something?