An invalid argument form cannot guarantee a true conclusion if given true premises. Alex is a man, and he's a good driver. If you find a conclusion that's wrong, the argument either has flawed premises or an invalid form. A conclusion is not necessarily wrong because it comes from an invalid argument. The argument just doesn't prove the conclusion.
Birds have eyes.
Animals have eyes. Therefore, birds are animals. The conclusion is true, but it doesn't follow from the premises. Rosa is a liberal.