diff --git a/src/system/game-data.ts b/src/system/game-data.ts
index 9bd0fcd0745..bbc74ee13e3 100644
--- a/src/system/game-data.ts
+++ b/src/system/game-data.ts
@@ -853,8 +853,8 @@ export class GameData {
         try {
           const sessionData = this.parseSessionData(sessionDataStr);
           for (let i = 0; i <= 5; i++) {
+            const speciesToCheck = getPokemonSpecies(sessionData.party[i]?.species);
             if (sessionData.party[i]?.abilityIndex === 1) {
-              const speciesToCheck = allSpecies[sessionData.party[i].species - 1];
               if (speciesToCheck.ability1 === speciesToCheck.ability2 && speciesToCheck.abilityHidden !== Abilities.NONE && speciesToCheck.abilityHidden !== speciesToCheck.ability1) {
                 sessionData.party[i].abilityIndex = 2;
               }