diff --git a/src/data/mystery-encounters/utils/encounter-phase-utils.ts b/src/data/mystery-encounters/utils/encounter-phase-utils.ts
index 9c569775f38..b98a6597414 100644
--- a/src/data/mystery-encounters/utils/encounter-phase-utils.ts
+++ b/src/data/mystery-encounters/utils/encounter-phase-utils.ts
@@ -636,11 +636,11 @@ export function transitionMysteryEncounterIntroVisuals(scene: BattleScene, hide:
       // Transition
       scene.tweens.add({
         targets: introVisuals,
-        x: hide ? "+=16" : "-=16",
-        y: hide ? "-=16" : "+=16",
+        x: `${hide? "+" : "-"}=16`,
+        y: `${hide ? "-" : "+"}=16`,
         alpha: hide ? 0 : 1,
         ease: "Sine.easeInOut",
-        duration: duration,
+        duration,
         onComplete: () => {
           if (hide && destroy) {
             scene.field.remove(introVisuals);
diff --git a/src/test/utils/overridesHelper.ts b/src/test/utils/overridesHelper.ts
index 257ec523399..4116810be5d 100644
--- a/src/test/utils/overridesHelper.ts
+++ b/src/test/utils/overridesHelper.ts
@@ -45,7 +45,7 @@ export class OverridesHelper {
    * @param encounterType
    * @returns spy instance
    */
-  mysteryEncounter(encounterType: MysteryEncounterType): MockInstance {
+  mysteryEncounter(encounterType: MysteryEncounterType) {
     const spy = vi.spyOn(overrides, "MYSTERY_ENCOUNTER_OVERRIDE", "get").mockReturnValue(encounterType);
     this.log(`Mystery encounter override set to ${encounterType}!`);
     return spy;