No, more then likely it's just he hasn't gotten there yet. When you tell your follower to wait for you at the Lucky 38, they walk there so depending on where you were at when you told him, it might take him a while to get there. I've told Lily to wait for me there while we were in Goodsprings and I ran to Vault 11 to wander around and an hour later I fast traveled to Freeside and she was walking past the Crier for Mick and Ralph's.
If I decide I wanna tell a follower to wait for me at the Lucky 38, I fast travel to the strip and go in and fire them there. Saves time waiting for them to get there when you wanna rehire them back.