When using norwegian locale nb_NO, the $Created.Ago functionality did not output right format.
I found the problem in the norwegian language file nb_NO.php in the lang folder under sapphire.
This two lines seems to be wrong:
$lang['nb_NO']['Date']['TIMEDIFFAGO'] = '%er siden';
$lang['nb_NO']['Date']['TIMEDIFFAWAY'] = '%er til';

So I changed it to:
$lang['nb_NO']['Date']['TIMEDIFFAGO'] = '%s siden';
$lang['nb_NO']['Date']['TIMEDIFFAWAY'] = '%s til';

And no it works as it should.
I've had this problem with SS version 2.3.3, 2.4.0 and 2.4.2. Truly it is a problem in all versions.

Actually I have no questions, just wanted to share this with other norwegian developers if they experience the same problems.
This probably qualify to open a ticket, but I'm not sure about how that's done...? (Well, that's a question)