depart and return flight dates are 2 months apart

I hold a Japanese passport and am going to stay in Shanghai twice for 2 days in July and 1 day in September, respectively, in two months time. The flight is a round trip from Japan. Between these two stays, I will be traveling to Europe. In other words, I like to book a round trip flight from Shanghai to Europe even though I originally travel from Japan. That is exactly why I'd like to stay in Shanghai twice in two months time. My question is whether my travel to Shanghai will be an issue only because the depart and return dates are 2 month apart. But again I only stay in Shanghai in total of 3 days, which is well below the no more than 15 day limit.
Thnak you.