It seems that whenever you click a move/transfer tutor, it only shows you the alive pokemon in your party. Which is fine, but if the first pokemon in your party is fainted and you click the first pokemon in the Tutor GUI (which would be the first non-dead pokemon in your party) it tried to tutor the dead pokemon in your 1st slot.
Steps to reproduce:
1. Have a dead pokemon in your first slot of the party, and a living pokemon (of a different species preferably) in a different slot
2. find/summon a move/transfer tutor and interact, choosing the first pokemon in the list that appears.
And, that's it, you can see the "chosen" pokemon being the dead pokemon in your first slot and not the one you chose.
(Sidenote, a related error seems to be that when you interact with either of the two tutors with *no living pokemon*, the game crashes.)
(Sidenote two, this error seems to be in the SelectPartyPokemonScreen class)