Is it possible for an insurance rep to have no clue who's actually in network?

So I'm on medicaid right now. Found an allergist on Zocdoc who would seemingly take my insurance, and she did when I went in for an initial consulation. I've got an appointment for allergy testing tomorrow, but I called my insurance to confirm whether or not it's covered. Person on the phone said they couldn't find the allergist in their network, so the testing wouldn't be covered. They had no idea what to say when I asked if it was possible that their listings simply weren't up to date.