That could certainly happen within 6 months if the watch had been left too long without servicing: oils, grease, gaskets.
Or the watch had previously received a knock that put something out of alignment, before it was in your hands. It may be still keeping good time and show no visible defects, but there are surfaces grinding on surfaces. Only when the watch is opened will that become noticeable, unless the dial gives us a clue.
In the service report that GO sent you I see "Replacement of Hands", and in Art's great follow-up "dial dislocation". These things usually don't happen without the application of brute force - I suspect on transit. Believe me, I have seen crates of precision instruments literally hurled into trucks, no matter how the warnings were marked on the outside or the careful packing inside. That hurts.
Briefly a worst-case scenario, not necessarily yours, but it would be bad enough for me:
The watch is out of alignment, has been put on a high-speed winder with the chronograph running, or has been delivered to some place with the chronograph running and left outside exposed to high temperatures and possibly bumped about some more.
As for timing, I am always curious about what other people expect for accuracy. Your part of the world has a different temperature span than Glashütte or their assembly chamber. A sudden change from scorching heat to air conditioning or vice versa, may have an effect - if not on the balance wheel then on the oils.
Of course, the wearing habits of the individual owner play a noticeable role, depending on how one "rotates" and if the watch was kept wound (also by hand) between intervals.
I hope for you that your communications with GO's Servicing Department will continue to improve - with Art's great help! - and that you will be satisfied with their results, and do not put GO on your black list for future purchases. Perhaps you will even grow closer.
My GO Senator Rattrapante was running a constant 12 secs too fast for a couple of weeks after buying it. I took it back to the AD, here in Hamburg, and it is now -1 to +3, depending on the position during the day or night - and of course worn - whether or not the rattra-chrono was switched on or not. I never leave the function running unless I am using it for its intended purpose.
I also have an ALS Double Split that had been losing 12 secs, regardless of the position. Now it is down to 6 sec - still a bit too much for me - but I am not going to do anything about it for a month or two.
Both are great watches, for what they do and what they cost.
I hope that I have not shown excess (or excessive) wear on your patience!
amerix
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