diff --git a/src/berry.c b/src/berry.c
index e66b106ca9..9f187bd1e2 100644
--- a/src/berry.c
+++ b/src/berry.c
@@ -2383,6 +2383,7 @@ static u8 GetTreeMutationValue(u8 id)
         return 0;
     myMutation.asField.a = tree->mutationA;
     myMutation.asField.b = tree->mutationB;
+    myMutation.asField.unused = 0;
     return sBerryMutations[myMutation.value - 1][2];
 #else
     return 0;