First off, thats just a minor bug since it does not keep you from playing the game or anything, though its sad when there is a tab where your K/D for campaign and other statistics are showed, which all stay at 0 for unknown reasons. I am now replaying the campaign on legendary, but it still says the only mission I finished is Osiris.
I hope this is connected to the other issues with connecting properly to XL Servers. Just wanted to raise awareness.