Doors and Windows - Loose deadbolt

The deadbolt lock on the front door leaves a false sense of security when you lock it from the outside with the key. You turn the key and "think" the door is locked, but in fact it is not b/c the lock is loose inside. When you turn your key to remove the key from the lock, the lock releases inside and unlocks the door again, instead of leaving it locked and secure.

Any ideas of what this could be and how we can fix it? Do we need to call a Locksmith?

If you are unsure how to proceed, by all means, call someone that knows. Is it a stand alone deadbolt, name?? Schlague, Kwikset. It may just need to be taken apart and cleaned/lubricated, if more than that, replace it.

Is this a newly installed deadbolt? If so, it may be that the hole in the jamb was not drilled deep enough for the bolt to travel its full length. Check the operation of the deadbolt with the door open. Does it work properly and stay out when you remove the key? If so, that is probably an indication that if you drill the jamb a little deeper it should work OK.