The bank will give a copy of a title that shows that the bank is the lien holder. If they have handed you clear title, go to the bank and report the error. You will only have problems later if you don't straighten it out now.
you should notify them of the mistake. If you don't you could be sued by the bank to recover the title. Depending on the circumstances there could be criminal charges
If this is not yours then make sure you give it back. Regardless if they gave it to you and you take some action you alone will be liable. One mistake does not negate how you proceed.
