diff --git a/src/data/ability.ts b/src/data/ability.ts
index d90f6d5c376..4c021297a94 100644
--- a/src/data/ability.ts
+++ b/src/data/ability.ts
@@ -4951,9 +4951,10 @@ class ForceSwitchOutHelper {
       }
     /**
      * For wild Pokémon battles, the Pokémon will flee if the conditions are met (waveIndex and double battles).
+     * It will not flee if it is a Mystery Encounter with fleeing disabled (checked in `getSwitchOutCondition()`) or if it is a wave 10x wild boss
      */
     } else {
-      if (!pokemon.scene.currentBattle.waveIndex && pokemon.scene.currentBattle.waveIndex % 10 === 0) {
+      if (!pokemon.scene.currentBattle.waveIndex || pokemon.scene.currentBattle.waveIndex % 10 === 0) {
         return false;
       }
 
diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index f14fc954c84..1dc4972af79 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -3101,10 +3101,10 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
   }
 
   lapseTag(tagType: BattlerTagType): boolean {
-    const tags = this.summonData?.tags;
-    if (isNullOrUndefined(tags)) {
+    if (!this.summonData) {
       return false;
     }
+    const tags = this.summonData.tags;
     const tag = tags.find(t => t.tagType === tagType);
     if (tag && !(tag.lapse(this, BattlerTagLapseType.CUSTOM))) {
       tag.onRemove(this);
@@ -3114,6 +3114,9 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
   }
 
   lapseTags(lapseType: BattlerTagLapseType): void {
+    if (!this.summonData) {
+      return;
+    }
     const tags = this.summonData.tags;
     tags.filter(t => lapseType === BattlerTagLapseType.FAINT || ((t.lapseTypes.some(lType => lType === lapseType)) && !(t.lapse(this, lapseType)))).forEach(t => {
       t.onRemove(this);
@@ -3122,6 +3125,9 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
   }
 
   removeTag(tagType: BattlerTagType): boolean {
+    if (!this.summonData) {
+      return false;
+    }
     const tags = this.summonData.tags;
     const tag = tags.find(t => t.tagType === tagType);
     if (tag) {
diff --git a/src/test/abilities/wimp_out.test.ts b/src/test/abilities/wimp_out.test.ts
index df965fc340d..4283386b248 100644
--- a/src/test/abilities/wimp_out.test.ts
+++ b/src/test/abilities/wimp_out.test.ts
@@ -613,4 +613,23 @@ describe("Abilities - Wimp Out", () => {
 
     confirmNoSwitch();
   });
+
+  it("should not activate on wave X0 bosses", async () => {
+    game.override.enemyAbility(Abilities.WIMP_OUT)
+      .startingLevel(5850)
+      .startingWave(10);
+    await game.classicMode.startBattle([ Species.GOLISOPOD ]);
+
+    const enemyPokemon = game.scene.getEnemyPokemon()!;
+
+    // Use 2 turns of False Swipe due to opponent's health bar shield
+    game.move.select(Moves.FALSE_SWIPE);
+    await game.toNextTurn();
+    game.move.select(Moves.FALSE_SWIPE);
+    await game.toNextTurn();
+
+    const isVisible = enemyPokemon.visible;
+    const hasFled = enemyPokemon.switchOutStatus;
+    expect(isVisible && !hasFled).toBe(true);
+  });
 });