HammUEr, a Hammer/Worldcraft map importer for Unreal Engine

I tried to see if I could replicate your issue and I cannot - however, I would say that as *VTFEdit *has a batch/bulk export option to convert an entire folder, you could choose this option and blanket-drop the TGA’s into *UE4 *and overwrite all of your existing files that were converted by HammUEr