Citadel 1 of 2 will only download as Citadel 2 of 2

I decided to download part 2 partly because I was tired of downloading part 1 over and over, and partly for Sh & Giggles. This seemed to do the trick. Now both parts 1 and 2 are on my hard drive. I don't know how or why this is - or if it'll actually work in game, but they're both there. Hope this helps.