Hi,
>>We recently moved to O365 and we've noticed that we don't always get a reminder on our recurring meetings.
Does this issue occur to specific recurring meetings? Created before migration?
If it occurs to specific recurring meeting, we can directly recreate this meeting.
Besides, if we create a new recurring meeting, will you receive reminders normally?
As far as I know, OWA doesn't have such a Reminder system which will pop up as overdue.
We can try following command switch to clear and regenerate reminders:
Please exit Outlook, press Win key + R to open the Run command, type outlook.exe /cleanreminders and then press Enter.

Any updates, please feel free to post back.
Regards,
Perry
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