I noticed something interesting on a professor’s ResearchGate profile. He says he’s both a visiting associate professor and a tenure-track associate professor at the same university and department, concurrently.
Can a visiting professor be tenure track in the same department concurrently?
In the US there are too many variations in rules and procedures to rule this, or most anything, out completely. But it would be unusual. It might be a failure to properly update the webpage you may have seen this on.
But an associate professor on tenure track has almost certainly earned tenure elsewhere (some exceptions) and might have been invited as a visitor as part of the hiring process. They might be in transition.
Joint appointments are also possible, where someone holds a position at more than one university.
But since you didn't see this on a university page, I'd guess it is just a failure to keep things updated properly (guess, not claim).
A further guess is that a visitor was offered an associate professorship and accepted, but a (short) pre-tenure period was needed, as is pretty typical. The "visitorship" might even have been to "take a peek" at the person prior to an offer.
