GW Mobility Outlook for Android issue


I have a GW Mobility issue, where the Outlook for Android app keeps sending "Mark Read" operations for the same email continuously.


But the item is already marked as read:

2020-06-18 14:50:17.076 DEBUG [WORKERS_POOL_Thread-10] [AppInterface:1427] [userID:xxx] [eventID:] [objectID:] [] Skipping markReadRequest (item already marked read). ItemId: 5EEB3683.XXX.XXX.100.1707439.1.22AFE.1@1:577A8330.XXX.XXX.100.1707439.1.67.1@13

This is not the only email, there are a bunch of them repeating again and again. The Mobility cannot keep up and request are piling up in the queue. I tried to reinit the user, did gwchecks, rebuild the mailbox, disabled the device, resynced it. I've even asked the owner of the device to remove the mailbox from the phone, I did a reinit and added back the mailbox to the device. Nothing helped.
Have you every seen such behaviour? How can I handle this?
(The user is of course the CEO )