i bought Premium for BF4 on One a few hours ago, but the 2nd Assault DLC won't show up, neither in the in-game store nor over the One marketplace. Btw the in-game store says Null Name, .

oh dude, im so sorry you decided to buy premium, from what ive heard its a total waste of money, apart from the small save where dlc is concerned, the rest of it is just camos and art work. its a total con AGAIN!

My friend and I are having the same problem.  We both bought the Premium for BF4 through Xbox One and we cant seem to find where to download the maps.  He also said we are missing some other things but not sure what he was talking about.  

I also have been droped from servers and completly kicked out of games and sent back to the xbox one home screen the last 2 days.  

That lack of join as a party sucks as well. 

While in game we cant join private chat party saying it cant connect.  this only happens if we are playing BF4.  If we create the party before joining the game it works.

have you tried downloading the premium download first? restart the xbox and re insert the game... it should then be available. it worked for me