When i purchased my jeep the key would pull out without hesitation while running, I was only provided 1 key so i swang by the dealer who took down my license information, checked my registration paperwork and cut a key based off of the vin number & that key does not pull out. comparing keys the original key was very worn.
i only use the original key as a backup now and the new key daily as i dont want to add any wear to the tumblers by using a worn out key.