Look guys, when you buy a car get it registered right away, even if you do not want to drive it for a while.
If you are successful at registering it then your state recognizes you as the owner. Titles will be in the owner's possession providing there are no outstanding liens. Title will be in the "lien holder" possession if lien outstanding.
What happens if you buy car and you don't register it and therefore you did not do a lien search? And as it turns out, it actually has an outstanding lien. 10 years later you want to sell car. Owner #1 is required to clear off lien...but he died years ago. You have to prove to DMV that you, owner#2 own the car before they release a copy of title to you to give to owner#3. And at same time some guy is trying to steal the VIN ownership from you.
Get the picture...get your car registered to protect your investment. You don't to keep it current if you are not driving it. You just need to be the last owner on record.
Sounds like something similar is happening here. Seller is a flipper that did not want the cost to register and sully up the owner history. Now he is really f'd.