Exchange 365/Outlook 2016 - Subsequent mail rules don't execute?

Exchange 365 mailbox.

Mail comes into the Inbox. SpamSieve rule (Exchange Client Rule) correctly moves it immediately to the InboxSpamSieve folder. Some seconds later, the “Outlook - Filter Mailboxes” triggers and moves the mail back to the Inbox. So far so good.

However, I have additional rules (against Exchange Client Rules, just like the SpamSieve rule) that should then process that mail and move it to a specific folder within the Exchange Mailbox. This does not happen - the mail remains, unread, in the Inbox.

It seems almost like Outlook does not recognise that a new mail has arrived in the inbox and therefore doesn’t process the rules against the new mail.

Previously my email was POP based and this setup worked perfectly.

Any ideas as to why this is happening, or is this an Exchange-only problem that I will need to work around? Or is it more like to be a configuration thing and if so, any clues as to where I should look?

I did check out “Filtering Other Folders” in the manual but this does not seem to be my scenario.

Grateful for your assistance.

That’s normal. Outlook only sees it as a new message when it first comes in.

I don’t know why this would be any different with POP. Were you perhaps using an older version of Outlook and a different SpamSieve setup?

It sounds like exactly the Filtering Other Folders scenario to me.