Is this sound normal for a freewheel?

So I just got my bike serviced in my LBS and as I was preparing my bike for a ride, I heard this grainy, sandy sound when the freewheel turns. (Hope you can hear it in the video, the sound is a bit faint compared to the freewheel ratchet noise but it's there if you listen carefully).

So the bike service includes bearing cleaning and re-greasing, I was wondering if there's any dirt that went inside the bearing, causing this sound.