Hi Brandon,
Thanks for your updates.
For "Yes, I can delete an entry on the local client", do you mean that the deleted items will come back after deleting them?
If you can delete them and they will not be back, you can do it as the workaround now. If the issue occurs the next time you create any recurring meetings, we need do more tests to identify the root cause.
Please do the test below(this test needs to involve your Office 365 Administrator to finish it):
1. Connect to PowerShell.
2. Run get-casmailbox.
3. Run set-casmailbox -identity yourmailbox -MapiEnabled $false.
4. Referring to the same command above, disable ActiveSyncEnabled, PopEnabled and ImapEnabled, only leave OWAEnabled"True".
5. After finishing the process above, only OWA can work. In this situation, create a recurring meeting in OWA and check if the same issue occurs.
To do this test, we can check if the issue is related to the Exchange Online server side.
In addition, I would like to also confirm if the other users in your organization encounter the same issue.
Any updates are appreciated.
Best regards,
Kid Yang
