The issues are more profound for universal mail-in voting, but it's not limited to universal mail-in voting. In MA, we have to apply for a mail-in ballot. This is what MA Elections Division said about mail-in voting in their FAQs section:

If I vote by mail, can I change my mind and vote in person?

It depends. If you mailed your early ballot back and it was accepted by your local election office, then your ballot is considered to be cast and you can't vote again. If your ballot never reached your local election office, or if it was rejected for some reason, then you can vote in person.

The issue I described is still relevant in MA, which doesn't have universal mail-in voting.

EDIT: This is another FAQ from the same page:

If I apply for a Vote by Mail ballot, does that mean I can't vote in person?

No. You can vote in person as long as you haven't already voted by mail. If you choose not to return your mail-in ballot, you can vote in person on Election Day or during early voting. You can also vote in person if you mail your ballot and it does not reach your election office by Election Day or if your mail-in ballot is rejected for any reason.

It sounds like in-person will Trump mail-in if they correctly cross reference the two ballots.