AssetRegistrySearchable(GetTagValue) doesnt work

UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "General", AssetRegistrySearchable)
	int32 StackSize = 1;
FAssetData AssetData;
	UAssetManager::Get().GetPrimaryAssetData(ItemID, AssetData);

	int32 ItemStackSize = 1;
	FName AssetRegistrySearchablePropertyName = GET_MEMBER_NAME_CHECKED(UItemDataAsset, StackSize);
	LOG_TO_SCREENF("PropertyName: %s", 5.0f, LOG_DEBUG, *AssetRegistrySearchablePropertyName.ToString());

	AssetData.GetTagValue(AssetRegistrySearchablePropertyName, ItemStackSize);
	
	LOG_TO_SCREENF("Item %s Stack Size: %d", 5.0f, LOG_DEBUG, *AssetData.AssetName.ToString(), ItemStackSize);


WHY?
please, help
thx.

P.S. StackSize Need Be 99