Rolex 1675 seconds hand falling problem

[Rameez-Q]

Hello

I have a rolex gmt 1675, the second hand sometimes goes all the way round, however sometimes it will not pass the 45 second mark it will get stuck but the watch will still keep time.

If the seconds hand is at 30 seconds and I shake the watch it will fall back to 10-15,20 seconds but will continue to go round.

I have attached a video of the problem

I have had it in my local jewellers first they said it was a problem with a pinion or one of the wheels now today they called me and told me the watch needs serviced however it was apparently serviced from the jewellers who I bought it from

I can send it back to the jewellers i bought from and they will fix it under warranty however i would like everyone's opinion as to what the problem is