This also happened to me (twice) with ms accounts used only to log into Skype. And I just migrated my Minecraft account 2 days ago, let's see how that plays out...
This just sounds to me like a "technically, you don't have to provide a phone number to create an account. Of course we will just lock it afterwards, but _technically_ it's not required..."
This just sounds to me like a "technically, you don't have to provide a phone number to create an account. Of course we will just lock it afterwards, but _technically_ it's not required..."