Featuring four Battlefield 3 maps reimagined using the Frostbite 3 engine, the DLC is a timed exclusive offering on Microsoft's next-gen console.
But a number of new Battlefield Premium members have reported being unable to download Second Assault after purchasing the DLC subscription package.
EA representative EA_Rick said on Battlelog: "I know some of you have said already that it is being looked into but I wanted to just confirm it for you so you guys have a blue post to refer to. Right now all I can say is that we are aware of this issue and are currently investigating this with Microsoft. Once we have some more details I'll be sure to let you know."
Second Assault is one of five Battlefield 4 expansions due for release by the summer of 2014. They can be pre-purchased as part of the £39.99 / $50 Battlefield Premium subscription offering. The other four expansions are China Rising, Naval Strike, Dragon's Teeth and Final Stand.