Sync read mails in systray & pulldown menu On a normal day, my phone is laying next to my laptop. Both are syncing emails and most of the time I read my emails on my laptop. The connection protocol is set to imap on both devices so when I open the email APP on my phone, the emails that are already read are marked as such. One problem is that this sync of read mails only happens when I start the email app. For each new mail , the systray is updated with the new mail icon and when I pull down the top overlay it keeps telling me there are X new email while they are all read(and also marked as such when i start the android email app).

This is really annoying as the blue LED is also flashing telling me there is something new while there isn't

Not sure if this matters but it's a samsung S4

Thx in advance!
Same thing happens with all Android phones (I've seen many phones). Just stop email notifications on your phone (for that particular account) if you don't want light flashing.
Every app checks for new messages as soon as you wake up the phone. This feature called as Push Notifications only checks for new messages but won't check if they are already read or not.