My 3861 Speedmaster is running fast.

So I've had my watch now for about 6 months, and I used to check it fairly regularly and it would gain around 3 seconds a day, which is totally fine. I hadn't checked it for about 3 months or so, and then I decided to try checking again when I was out for a walk with my Dad.

I was shocked that it was apparently running at over 12 seconds a day. I thought I must have screwed up somehow when I took my initial measurement that morning, because apparently the watch had gained around 4 seconds in the space of 8 hours. So I checked it again over the next couple of days, and it dropped back to its normal 3 seconds a day.

Then I went out for a walk with my mum, and I decided to check it right after the walk, because I wondered if walking fairly vigorously with the watch on had caused it to speed up or something. After that walk I found that the watch had jumped another 4 seconds, and was now running at around 25 seconds a day.

So, as an experiment I decided to leave my watch on my desk for 24 hours to see how much time it gained not on my wrist or moving about at all for a whole day. It gained over 6 seconds just sitting on my desk doing nothing.

Is this sort of thing normal for a movement as it gets a bit older and "breaks in" or do I need to send it back to Omega to have them look at it?

I mean, even though it seems to have jumped around a lot, over the last 4 days it's been averaging around 5.5 seconds a day and gained around 22.6 seconds in total. So maybe it's normal, but it feels like the watch shouldn't be doing that. Can you give me some advice?

Why do you check it all the time?

Was the Watch fully wound? Movements usually goes faster at the end of the power reserve. Even though METAS certified movement shouldn’t differ as much.