Office 365 Directory Based Edge Blocking support for on-premises Mail Enabled Public Folders

We just ran into an issue where emails to our mail enabled public folders in Exchange Online were failing, but only from our on premises relay.  The error returned by EXO was "550 5.4.1 Access Denied"  After working with MS Support, they directed me to this article where it seems that DBEB isn't supported for mail enabled public folders in EXO and hence, all accepted domains (including the onmicrosoft.com ones) need to be flipped to "internalrelay".  We had already flipped our primary domain, but not the onmicrosoft ones.  I was surprised to learn about this, especially since it had been working perfectly for years but all of a sudden on 1/6 this mail flow stopped working for us.  Since this article is now 3.5 years old, and still linked by this seemgingly relevant and up to date KB article:  https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/use-directory-based-edge-blocking I am wondering if there is any update to how DBEB performs in regards to mail enabled public folders hosted by EXO?