diff --git a/PKHeX.WinForms/Subforms/Save Editors/SAV_EventFlags.cs b/PKHeX.WinForms/Subforms/Save Editors/SAV_EventFlags.cs
index 8306d90d7..387d4c4b5 100644
--- a/PKHeX.WinForms/Subforms/Save Editors/SAV_EventFlags.cs	
+++ b/PKHeX.WinForms/Subforms/Save Editors/SAV_EventFlags.cs	
@@ -177,7 +177,9 @@ private void ChangeCustomBool(object sender, EventArgs e)
             if (editing)
                 return;
             editing = true;
-            if (FlagDict.TryGetValue((int)NUD_Flag.Value, out var chk))
+            var index = (int) NUD_Flag.Value;
+            Editor.Flags[index] = c_CustomFlag.Checked;
+            if (FlagDict.TryGetValue(index, out var chk))
                 chk.Checked = c_CustomFlag.Checked;
             editing = false;
         }