Android devices marking email read on pc with POP account

I have 2 different Android devices (1 Samsung Galaxy S3 and 1 Sony Experia).
I set up Outlook email (from Microsoft Exchange server 2003) for POP3 as the user wants all emails to be left as unread on PC. IMAP is NOT an option nor is Active Sync. When emails were received on PC they did not get marked as read until someone actually marked them as read. This was fine for approx. 6 months. We recently changed the setting in the Reading Pane so that the emails weren't opened when viewed in reading pane. About 2 weeks after doing this, all the emails are now marked read when the email app on the phone is opened. The emails haven't been opened, but all emails on the PC are now marked opened. When you get 25 to 50 a day, that can be a real problem!!!!!
I tried to set up email on the Experia and when I did, the same thing happened.I tried to set up a different email address, same problem.

NOTE: My iPhone works properly. Not marked read until actually read.

Can anyone help???? So frustrating!!!

 

Do you know if it works with Pop3?
I thought it only worked with Exchange Active Sync. Please correct if I'm wrong.

 

Not sure what you mean when you ask if the app has been updated? Do you mean the "Stock App" on the device.
We haven't tried Touchdown yet as I want to find out if it works the way I want it to with Pop3.