Here's a new one on me; or maybe I'm old enough to have forgotten I knew this once.
Had a bathroom door that wasn't latching. Lot of good to have a privacy lock on it! Thought the builder had fixed it when they did the 11 month warranty work on the house. It must have latched securely for a little while.
Well the other day I pulled on the door (from inside the room) while it was still locked, and it opened. I am not happy about this. I messed around with the strike plate trying to get it to protrude more and catch the bolt in the mortise. No dice. I tried to "persuade" the wood stop (which is obviously not plumb with the door) to move over a little. No dice.
I got out the tape measure and compared this door to two others. All three had their strike plates at the same height. But the stubborn door's knob was lower by more than 1/4 of an inch. So, I called the supplier, thinking I might need to replace the door with one from the same stock.
They sent a guy out yesterday. He removed the bottom and middle screws from the frame at the top hinge and replaced them with longer screws. The door now latches!
The explanation: the longer screws go into the stud, drawing the wood frame in. This alters the angle of the door, and raises the knob enough to let the bolt extend all the way into the mortise. I can see that the space between the door and the frame diminishes towards the top. The shorter screws only secured the hinge to the frame.
Only your carpenter knows such amazing tricks!