G'day,
if it´s new (that is, bought from an authorized dealer within the warranty period), i´d personally try to work it out with the AD who sold it.
Usually models bearing movement based on a GP3XXX caliber, which includes reference 25850, are known to be trouble-free and reliable.
On the other hand, as with anything hand-made (and all GP´s propietory calibers are finished and assembled by hand), exceptions are hard to prevent. But that´s what the warranty is for and therefore best to do is to get in touch with your AD.
Cheers,
Peter