It's a bug, you should look at all the threads on here regarding it, lots of people complaining over the app update released. Not much you can do and hope Samsung will release a fix soon.
Iv'e found a fix to the email sync problems. Look in the email settings, click notifications where you set your notifications then click in the notifications categories it should bring up the full list and if your email sync notifications is toggled on then you just unable the toggle to off that should stop your phone given out the notifications everytime you restart your phone.