New Outlook not adhering to PersonalAccountsEnabled unless I revert to Classic outlook

We implemented the  PersonalAccountsEnabled  = $false in out OwaMailboxPolicy, as below

Set-OwaMailboxPolicy -PersonalAccountsEnabled  $false -identity OwaMailboxPolicy-Default

I waited overnight and accessed a computer using my account and continue to be able to add Gmail and other personal accounts to my corporate New Outlook. I also removed my corporate account and readded it to New Outlook , restarted and same behavior of being able to add Gmail and other personal accounts.

I reverted back to Classic Outlook and restarted  Classic Outlook and enable New Outlook and the policy worked and prevented me from adding Gmail and other personal accounts. 

Is this the correct behaviors as I would expect the setting to take affect without having to revert to the Classic Outlook. It seems as if New Outlook is not reading the policy except on the initial movement from Class to New.