wondering if anyone can advise on what would cause this issue I am experiencing, sadly it's with one my gens 
right after the watch has been fully wound the watch runs VERY fast for the first hour. It will gain 2-3 minutes within the first hour, but after that it will settle down to a pretty good timekeeping.
scenario:
I fully wind the watch and set it at 9:00am, by 10:00am the watch will be showing 10:03am, at 11:00am it will show 11:03, and at 12:00 it will show 12:03. This shows the movement is only running fast during the first hour after it is fully wound.
I read that this is something to do with the mainspring?
Now what is frustrating me more is that I've sent it to the service center to get it sorted and they called today just to say it's normal and the standard procedure is that they will fully wind the watch and let it run for an hour or so before checking it on the timegrapher. Yes I agree that this would be fine in normal situations when you just want to check if the normal beat rate of the watch is fine, but my issue is exhibited within the first hour of the watch being fully wind. They had the nerve to try reassure me that the watch is fine, and after only me very nearly shouting at them that not it is not fine, the watch that is unable to keep time from being fully wound and the time set is no good, did they offer to run the extended test where they would wind the watch and check the timekeeping on a daily basis to see if it had been keeping or loosing time each day.
right after the watch has been fully wound the watch runs VERY fast for the first hour. It will gain 2-3 minutes within the first hour, but after that it will settle down to a pretty good timekeeping.
scenario:
I fully wind the watch and set it at 9:00am, by 10:00am the watch will be showing 10:03am, at 11:00am it will show 11:03, and at 12:00 it will show 12:03. This shows the movement is only running fast during the first hour after it is fully wound.
I read that this is something to do with the mainspring?
Now what is frustrating me more is that I've sent it to the service center to get it sorted and they called today just to say it's normal and the standard procedure is that they will fully wind the watch and let it run for an hour or so before checking it on the timegrapher. Yes I agree that this would be fine in normal situations when you just want to check if the normal beat rate of the watch is fine, but my issue is exhibited within the first hour of the watch being fully wind. They had the nerve to try reassure me that the watch is fine, and after only me very nearly shouting at them that not it is not fine, the watch that is unable to keep time from being fully wound and the time set is no good, did they offer to run the extended test where they would wind the watch and check the timekeeping on a daily basis to see if it had been keeping or loosing time each day.