I have roughly 30 Group calendars that are constantly being updated by CSRs and Project Managers to update shipping schedules. We are running into the issue where events are entered into Outlook and attachments are added. The event saves fine locally in the users Outlook, but it does not sync to O365 for others to see on their calendars. I've already checked file names and made sure they are acceptable (they are) and when entered in, exactly the same manner, everything works. If I wasn't bald, I'd be ripping my hair out. Can anyone help me with this?
I would suggest opening a supporting case and reporting this, especially if you can reliably reproduce it. My other suggestion would be to use a shared mailbox calendar instead, which are now accessible on mobiles as well and offer better calendaring functionality compared to Groups.