Yes, likely it was a 301 or 302 temporary redirect passing PR that hasn't been updated yet by whatever PR checker you were using.
This is really common and you'll find this daily at the expiring domain auctions. A lot of times it's a legit business that was using a different domain and decided to redirect it to another domain.
For example, this domain
http://www.rossinifestival.us was at the Godaddy $5 "buy it now" auction the other day and showing up as a PR 4 on most tools. Even a info:rossinifestival.us passes the :info and index test in Google.
However, you'll see zero backlinks with SEOmajestic, AHREFs and SEOmoz. Huge red flag. Actually, the red flag began waving when this domain made it to the $5 buy it now section -- you will almost never see a legit PR 4 domain with a good backlink profile go for just $5.
Let's take another example related to the domain above --
http://rossinifestival.org
You can see this redirects to
http://www.knoxvilleopera.com/rossini/
But if you plug this into AHREFs, it doesn't detect this.
SEOmoz and MajesticSEO tools do catch this 302 redirect --
This is why it's extremely important to do your due diligence and not rely on one SEO tool since it's impossible for anyone of them to be 100% accurate every time.
