Even cars right when you drive them off the dealer lot, they experience some type of problem after a few days, a week, or couple months.
This is what happens with mechanical machines. Stuff breaks. It happens all the time in any industry.
To get the watch back to you in 10 weeks is very acceptable in the watch industry world. Yes, I wish turn around time is faster but that's how it is. One of my watches, I didn't get back for 6 months and another 5 months. So 10 weeks is nothing IMO
And the fact that you're the 2nd owner of the watch, you're buying a used watch. Who knows how the original owner treated the watch. Whenever I buy a used watch or car, I have the higher expectation of it malfunctioning because I don't know if the original owner babied and cared for it.
Cheers,
Anthony