Outlook creating IMAP folders even though forbidden by ACLs

Hi!

Is it well known that Outlook cannot process RFC 2086 or RFC 4134 ACLs?

We are using Outlook 2013, 2016 and 2019, and with 2013 can definitely create shared folders with content that are not saved to the server, even though Outlook 'pretends' quite erroneously that they are - black hole for critical email that we must keep according to engineering contracts for design documentation purposes.

Thank you!

Matt Grant