Exchange Online - Problems with Quarantine Email

Hello All

I've observed an interesting pattern regarding quarantine emails. A customer of ours had some isssues sending emails because of a misconfigured SPF Record. The emails were held in quarantine (as they should) and quarantine emails were sent to the mailbox. However, instead of containing all the emails that were quarantined in the notification timeframe (4 hours), the system seems to have grouped them by subject and only displayed a single entry (other emails with different subjects appeared correctly). This means that instead of seeing 20 emails our client saw a single email with that subject line in his quarantine report.

I couldn't find any documentation from microsoft regarding this. Has anyone ever experienced this and is there a fix available?

Kind Regards