Issues with Delegated O365 Room Resource Meeting Notifications and Approvals w/Hybrid

[Geoff]

1. 
   
2. I have Exchange 2016 (latest CU) and O365 E3.
   
3. I have users mailbox's in both environments.
   
4. I have created an O365 room resource via 'New-RemoteMailbox'
   
5. I have then edited it to require approvals from delegates, the delegate is an O365 user with an EXO mailbox.
   

When an on premises user organises a meeting in the room the following happens:

• 
  
• There are no notifications sent out to the meeting organiser that the meeting requires approval.
  
• forwarded approval requests have no accept / deny /etc buutons for the delegate.
  

So have I missed a setup step or is there a config issue, bug, hybrid mode limitation I am not aware of here?