I did a search on this thread and had to reply..... I had the same issue last night with my new GMT 116710 LN. The date flipped half way between 12 and 13. My first thought was, DAMN...lucky 13. Anyhow...I changed the hour hand up, and it flipped to 13 fully....then back an hour and it flipped to 12 fully. That tells me that everything is working fine. Let's see what happens tonight, before any red flags go up. I'm sure it's just a lubrication issue. I don't want to open this watch, it keeps perfect time. One second slow after 7 days!.