ub fix for OOB access with gActiveBattler

src/battle_controllers.c

@@ -57,6 +57,11 @@ void SetUpBattleVarsAndBirchZigzagoon(void)
     gBattleControllerExecFlags = 0;
     ClearBattleAnimationVars();
     ClearBattleMonForms();
+// UB: at the start of a battle CheckMoveLimitations is called with gActiveBattler 
+// from the previous battle, which can lead to multiple arrays being accessed out of bounds
+#ifdef UBFIX
+    gActiveBattler = 0;
+#endif
     BattleAI_HandleItemUseBeforeAISetup(0xF);
 
     if (gBattleTypeFlags & BATTLE_TYPE_FIRST_BATTLE)