I had a strange situation this week while working on a customer site. The customer had purchased Enterprise Mobility Suite licenses and I had added some licenses to test users. So far so good. These users now had access to Azure AD Premium features - or did they?
I tired to configure password writeback for these users but it just didn't work, with no indication where the problem might be.
It seems that there is a known issue that Microsoft are currently investigating. In some cases, even if you add the EMS licenses to users it looks that Azure AD Premium just does not get activated on the tenant. It's easy to solve this with a free support call to Microsoft CSS. However I wanted to share this to prevent others wasting time second-guessing their configuration.
You can create an online support request via Office 365 or Azure Portals.
I hope this helps. Until next time.......