Gibraltar has an open border with Spain, which is nowhere near fully vaccinated. They've had an uptick (a few hundred cases since April, though almost no deaths). It seems rational to think that most of those cases among the vaccinated were brought there by unvaccinated people from Spain, and are not running wild in vax-to-vax chains of transmission.

The only "news" pieces I could find about Gibraltar having some massive surge were from hardcore antivax websites - the top one was something called welovetrump.