Hi micjensen,
Thanks for your update.
Given the current situation, I’d like to confirm the following information to narrow down if it is a mail flow delay issue or a client sync delay issue:
1. Have the affected users set up the Office 365 account both on iPhone and Outlook 2011 for Mac?
2. Are these users in the same Office 365 tenant or different tenants?
3. Could you please send a test email to one affected user, then check if it is received Outlook Web App (OWA), then check both iPhone and Mac Outlook ?
Best Regards,
Bruce Zhou