diff --git a/PKHeX.Core/Editing/ShowdownSet.cs b/PKHeX.Core/Editing/ShowdownSet.cs
index 13ed55253..fe63be407 100644
--- a/PKHeX.Core/Editing/ShowdownSet.cs
+++ b/PKHeX.Core/Editing/ShowdownSet.cs
@@ -282,9 +282,6 @@ public ShowdownSet(PKM pkm)
             string[] Forms = PKX.GetFormList(Species, types, forms, genderForms, pkm.Format);
             Form = pkm.AltForm > 0 && pkm.AltForm < Forms.Length ? Forms[pkm.AltForm] : string.Empty;
             Format = pkm.Format;
-
-            if (Form == "F")
-                Gender = string.Empty;
         }
         private void ParseFirstLine(string line)
         {
diff --git a/PKHeX.Core/Legality/Checks.cs b/PKHeX.Core/Legality/Checks.cs
index 79fe1752f..363db6d9b 100644
--- a/PKHeX.Core/Legality/Checks.cs
+++ b/PKHeX.Core/Legality/Checks.cs
@@ -2214,6 +2214,10 @@ bool IsValidPikachuCap()
                         return;
                     }
                     break;
+                case 678: // Meowstic
+                    if (pkm.AltForm != pkm.Gender)
+                        AddLine(Severity.Invalid, V203, CheckIdentifier.Form);
+                    break;
                 case 773: // Silvally
                     {
                         int item = pkm.HeldItem;
diff --git a/Tests/PKHeX.Tests/Legality/Illegal/AltForm/678-01 ★ - Meowstic - 01873505869C.pk7 b/Tests/PKHeX.Tests/Legality/Illegal/AltForm/678-01 ★ - Meowstic - 01873505869C.pk7
new file mode 100644
index 000000000..4972082f2
Binary files /dev/null and b/Tests/PKHeX.Tests/Legality/Illegal/AltForm/678-01 ★ - Meowstic - 01873505869C.pk7 differ