Built in Mail app for iOS devices showing "Unread" for Active Sync servers.

Built in Mail app for iOS devices showing "Unread" for Active Sync servers.

Since the last iOS update all my Active Sync Zoho mail accounts are showing every e-mail as unread even when it's been read in Webmail and desktop mail apps (running IMAP)

I've tried adding Active Sync to the desktop instead but it rejects being added to Apple Mail. It's only bee happening for the last couple of weeks but happens on my iPhone X and two iPad Pros.