All e-mails starting at a random date and time are being deleted one or more times a day on Outlook 2016 latest updates on Windows 10 latest updates

Question

User keeps her inbox cleaned out manually so that only the most recent e-mails are present until she has a chance to read and either delete them manually or move them to a specific folder to categorize them.

Suddenly about 3 weeks ago e-mails started getting deleted from her inbox and sowing up in her deleted items folder that she had not yet touched. These are NOT threaded e-mails they are just regular e-mails that are listed in her inbox as they arrived. One minute they are there and the next they are gone. This happens at random times and will happen one or two times a day. It never deletes them all. It will start at some random date and time and delete everything from there to the end of her inbox. We can and have moved the deleted e-mail back to her inbox multiple times but it will happen again the next day at some random time. there was an exception, last week I turned on Outlook Advanced Troubleshooting logging and it didn't do it again for almost a week. but then it started doing it again. I imported the logs into the event viewer but they was of no help whatsoever as they did not contain and event message text, just event numbers and key numbers. I assume Microsoft has some software to evaluate these logs that I do not have access to. I turned that logging off and now it seems like it is worse that it was before.

The environment is as follows:

Computer having the problem (This is the only computer on this domain network having the problem):

6 month old Intel i7, 32GB RAM, 500GB SSD Clone Running Windows 10 with latest updates

WebRoot SecureAnywhere Antivirus

Office 2016 with latest updates

Act! Desktop 2021 has a Outlook addin but it is disable and was never configured used

Timeslips has an Outlook addin but it is disabled and was never configured or used

Connected to a domain network with 5 other computers

Connected to a Windows 2016 Server standard edition Domain Controller with latest updates

With Exchange server 2016 with latest Rollup

No other problems have been exhibited on this computer.

User has an iPhone and iPad conneted to this mailbox using the apple mail app (not in use most of the time when these e-mails get deleted most of the time)

User also has a Windows 10 laptop also with latest updates with Office 2019 with latest updates connected to this mailbox (not in use most of the time when these e-mails get deleted)

Network:

All Gigabit wired network with dell gigabit switch

Sonicwall TZ400 Firewall

Server:

Windows server 2016 Standard Edition Latest updates

Exchange server 2016 Standard Edition Latest Rollup

Other issues:

No other issues

No other users having this issue

What's been don so far:

Deleted and recreated users OST file

Deleted and recreated users Outlook User Profile

Performed a complete computer cleaning and multiple vendor virus scan including Malwarebytes, Adwcleaner, Hitman Pro full scans, nothing found.

Used Microsoft Uninstall tool to perform a clean uninstall of Office, restarted computer and reinstalled office (Did not delete Outlook registry entry or local or roaming folders, That will be next).

Checked and disabled all Add-ins except the default Microsoft addins in OWA

Checked both Outlook and OWA rules and there were none.

Nothing has changed on the network or her computer when this issue started except possibly a Windows or office updates that we are aware of.

I've researched this to death and checked and or performed all of the usual steps for file or profile corruption with NO change in outcome. I've been a highly skilled IT service tech for a very long time and have over 200 customers using similar systems and none have ever had this issue and I'm stumped.

If you have any suggestions that are just a copy and past of the same old tired recreate the profile or similar please chime in. I need some new ideas.

I reset the users password and the problem continues.