Longines watch problem

Question

Hi, my friend has a ladies titanium Longines watch, battery operated. It's about 9 years old, for the last year now, it works for about 4 weeks than loses about 3-4 hours quite suddenly, during this time of losing, the 2nd handle literally jumps every 5 seconds instead of going around smoothly. It has been serviced and looked at by 4 or 5 different watch repairers... all are baffled and say there is nothing wrong... but I have seen the problem and it is there!!