I tested this inside out on the PTR yesterday. From my understanding what must be happening under the hood is that the nameplateShowAll which was moved in the interface options panel has no more affect on the game when it comes to friendly npcs.
The CVAR
does get saved properly. It just has no effect.
The friendly nameplates behave as if that value is disabled. Means the friendly npc nameplate pops up when you target the unit.
I tested combat mode. Does not change a thing. Nameplates stay hidden unless you target one manually.
Enemy nameplates show up fine. Friendly nameplates on the targeted npc show up fine.
p.s. I repaired the PTR installation twice. I ran no addons. I reseted all settings to default multiple times. I tested all possible nameplate interface settings. Bug is consistent.
http://eu.battle.net/forums/en/wow/topic/17613761364