Outlook People: contact list/category synchronization

Outlook People lists do not seem to synchronize with Windows Live Mail. Some repro steps, in which Account A is an account that has been upgraded to Outlook Mail:
 

 
1. Create a new list on the Outlook People page for account A and populate it.
    The list is not synchronized with Windows Live Mail 16.4.3528.0331 or 16.4.3564.1216 and never appears in either.
    
2. Create a new category in Windows Live Mail 16.4.3528.0331 while signed in with account A.
    The category is not synchronized with Outlook People and never appears there.
    The category is synchronized with Windows Live Mail 16.4.3564.1216 and appears as a category there.
    
3. Create a new category in Windows Live Mail 16.4.3564.1216 while signed in with account A.
    The category is not synchronized with Outlook People and never appears there
    The category is synchronized with Windows Live Mail 16.4.3528.0331 and appears as a category there.
    
   

None of the three lists/categories appears in the Windows 10 People app.

Can anyone confirm that contact categories created in Windows Live Mail while signed in with an account that has been upgraded to Outlook Mail synchronize between instances of Windows Live Mail regardless of program version?

Can the forum support staff confirm that the product team is aware of this weird behaviour? That categories synchronize between Windows Live Mail and contacts.live.com, but that Outlook People is apparently unaware of them?