seems like they have something official on this now too as i got pointed to this by EK the other day

under their FAQ Booking with Emirates:

If you entered multiple first names, or multiple family names for a passenger, it is entirely normal for the names on the ticket to be joined together, even if you had entered them separately when booking online. For example: if you entered Mr John Adam Smith when booking online, your ticket will show the name as SMITH/JOHNADAMMR. This is standard airline industry practice.