I have this crazy event happening with some of my users using Outlook 2016 and using OWA with an Exchange Online mailbox. I am having trouble figuring this one out, so I thought I would reach out to the community. I know this issue is not a local issue because when you bring up OWA it shows different times as well (3rd screenshot below). So with this, it rules out anything internally, .ost, .pst, I even ran the 'outlook.exe /cleanreminders' just to see what would happen with the user not even in cached mode - same issue. I have even gone about having the organizer remove the reoccurring meetings, create a new reoccuring meeting with a different subject line, same issue.
Also, another thing to add is how is this possible considering you can only do a maximum of two weeks for a reminder. Nothing has changed (mailboxes have been in Exchange Online since 2017) nor can you set this setting with any policies at least not that I know of. Has anybody seen this before? I am 99% sure this is Exchange Online issue, however I have been wrong before. Feel free to chime in if you have any ideas.
Thank you for your response. I have gone through the calendar options for the users having the issue and they are set for 15mins with the results still being the same from the screenshots I posted. I tried toggling it in OWA, toggling it in Outlook...same results no matter what I do. If I take the calendar invite that has the reminder issue and set it to whatever time (example 1 week) it reverts back to the crazy numbers.
I connected to Exchange Online PS and ran those commands, I get the same result as if I were to go into the calendar options on the client. See below:
I have a support case open with Microsoft, but nothing has been resolved yet. I am really at a loss on this one. I am almost positive its on the Exchange Online side, has to be. Any more ideas?