Can a dealer sell a car without the title?

I purchased (financed) a 2018 car the other day but the salesman told me that they aren't currently in position of the title and the previous owner who I assumed traded in the car still has it in their possession and hasn't brought it into the dealership yet. They said it might be a few days or a week before they would have the title (obviously I don't have the vehicle yet) I called the dealership the other day to ask about it and left a voicemail but nobody got back to me. Paperwork and everything is signed and alls that's left is the title. I was wondering if anyone has ever ran into this situation before? Are dealerships allowed to accept trade ins without titles? This is also a pretty big dealer in the area. Thoughts?