User blog:Theory of everything/Is Nick loosing his Grimm powers?

In "Organ Grinder" Nick didn't realize he was in the presence of three Geiers! Is he loosing his Grimm powers of perception or do these Geier creatures have a stronger ability to control their appearance to humans, including a Grimm?

Or maybe Nick was too distracted worrying about whether to tell Juliette that he's a Grimm. What do you think?