In other cases I've heard stories about situation X or Y from people who were there, which were flatly contradicted by other people who were also there but saw it from a different angle.
I can believe that the Norwegian navy & MoD might be putting the most optimistic spin on things, but outright lying seems unlikely. One can imagine, for example, that one of Roald Amundsen or Thor Heyerdahl is undergoing significant maintenance, while the other is berthed for lesser maintenance & theoretically capable of putting to sea if needed, & Helge Ingstad might be undermanned while some of the crew are on leave but also theoretically capable of putting to sea - & this is interpreted by those who've heard the scuttlebutt around the base as all three ships unusable, while the navy prefers to (truthfully) say that two are usable, while keeping quiet about certain details which explain why those two ships aren't going anywhere for a little while..
That sort of clash of information & interpretation isn't exactly unknown.