Mail notifications not removed from iPhone after reading the mail on Mac?

[johannnn]

I use iCloud mail on my iPhone (iOS 10) and Mac (Sierra). Both on wifi.

1. I get an email
2. A notification is received on both my Mac, as well as the lock screen and dock icon on the iPhone.
3. I read the email on my Mac.
4. Regardless of how long I wait, the notification on the lock screen and dock icon won't get away.

Shouldn't everything iCloud sync all the time and in the background?
At the moment I have to actually open the Mail.app and wait for it to synchronize.

 

[breather]

I just switched to iCloud mail and discovered the issue is still there. Is there a setting, a hack or something to fix this?
I thought the synchronization between my Apple devices would be lightning fast since its... you know... Apple.

Its quite annoying.