What I'm wondering if this movement is prone to this type of problem and whether it may be a recurring issue.
Also, it may be a good idea to find out preferably in writing as to what happened. Later on, if the same issue occurred again (outside of warranty), I'm wondering whether Patek would do something about it...
The timepiece required a new balance complete. The reason for this is because the hairspring suddenly
broke. lf you are going to replace the balance complete, then you have to completely overhaul the movement.