Did you have them all in your inventory at once? Some of the collector trophies imply you have to have them all at the same time - although that was not my experience with the emblem trophy, so I'm not sure which way is the bug.
@Miss Nomer You can spend your first emblem of Lem now, if you like. You'll just have to earn another Lem emblem before getting that trophy. A matter of preference and priorities :)