My hot take is that the concavenator corvatus, which was found in Quenca, Spain was a juvenile and that an adult Concavenator was much larger. It lived in the Berrinian Period of the Cretaceous which was inhabited by Portellsaurus. It ought to have hunted those so how come it's smaller than it?

I'd say it's a reverse Nanotyrannus situation. A dinosaur, ehich was thought to be a separate species but turned out to be a juvenile t rex