The door handles on a number of my rooms do not seem to lock. They're all privacy levers with turn button on the inside and emergency key on the outside. I believe they are the Galiano model by Weiser.
The problem seems to be that the turn button doesn't turn all the way and thus doesn't engage the lock. As you can see in the pictures below, it only turns about 45 degrees before it stops. From my experience with other door handles, it should turn 90 degrees in order to lock.
What would cause this? Can they be repaired, or do they need to be replaced?
Images of the handle with turn button in normal (unlocked) position, and partially turned:
Detail of the inside of the side with the turn button: