Nah. Cook has pretty much said that the decline is because of the massive sales of iPhone 6's last year and then the influx of the 6S during the Chinese New Year a few months back. Basically, very few new iPhone buyers left willing to buy mid-year in China. So yeah, a minor decline in sales is expected in this Quarter and maybe even the follow on quarter until the iPhone 7 release.
Personally, I think that was why they released the iPhone 5S aka SE; To help mitigate the financial loss with a high profit, low cost iPhone that they already had assembly lines tooled for.
Good call.
I understand some of the complaints, but I'm happy about the SE. I'm always up for more competition in the small-to-midsized smartphone space.