Slow Date Change on AP 15300 (Serviced 2020)

[Royale With Cheese]

Hi All,

I recently purchased a secondhand AP 15300 from a local (trusted) dealer. This was not a boutique nor AD.

The watch included all original paperwork, manual, warranties and box. Everything in excellent condition.

The original sale was dated 2010. The seller was very clear that the original owner had basically left it boxed for a number of years and that when it was brought to him the movement had dried up and therefore it was serviced just the month prior, but not by AP rather a local watchmaker.

Besides a bit of visible re-brushing work, everything else looked excellent. Movement function seemed perfect.

After a week on the wrist, the calibre 3120 is running perfectly accurate, and no issues with power reserve either. However I have noticed that for some very strange reason, the date change is not instant as is should be on this movement.

The DW will begin cycling around 10:30pm, by 11~11:30 it will be perfectly in-between the two transitioning dates. Then roughly about 12:00 (on the dot), it will be completely transitioned over onto the correct date.

From everything I understand about the cal.3120, this movement should be an instant date change. I have seen few videos where the date flips over roughly right around midnight - there is no gradual shift between the dates.

While functionally there is no "issue" as such... However still I have some concerns about this now. I'm not sure if there is something wrong with the movement, or whether something has been damaged during its service work, or if a part is possibly missing..?

Quick pic of the date transitioning last night: https://i.imgur.com/IzAeELj.jpg

The instant date flip was a feature that was prominently advertised by AP on introduction of this calibre, so it concerns me that it's not performing as it should.

Has anyone with a 3120 experienced this with their datewheel?

I have read other forum where owners have experienced date wheels getting "stuck" in-between dates, but as far as I understand - this is a bit of a separate issue as the movement is still flipping the date instantly prior to getting stuck.

I would just like to understand if this might be normal for the 3120 after a decade, or if there is something that needs my immediate attention.

Planning to take it to my local AP boutique when I can find some available time. In the meanwhile hoping to hear some thoughts from the experienced members here!

Thanks in advance for any input.