read/unread flag not syncing between outlook and android

I'm running outlook (IMAP) and my phone is a note 4 using msync.zoho settings. I also have my work email (exchange syncing to my note 4. If I receive an email, it arrives successfully on both my computer and phone. If I open the message on my phone, it changes from unread to read status on both the phone and computer. Likewise, if I mark a message as unread on the phone, that status is passed to outlook on the computer. However, if I open the message on the computer first, it never shows as read on the phone, nor is the status changed if I mark a message as unread on the computer. This is a new behavior, starting sometime within the last month. I see no significant updates on either the computer or the phone having to do with email. I even went so far as to delete and reconfigure the msync account on the phone, which correctly marked the mails as read/unread for about a day, and then the bad behavior started again.

Can you offer a solution?

Thanks!