The optional objective to secure a gold mine in A Dark Covenant does not work it might be because i play on hard.
this post shows that the problem is more then 6 months old:
also this guy made a long post about bugs (mine included ) hope you see it, there is no blizzard people posting that they have seen it: Reforged Campaign on Hard difficulty bug report and feedback
Update: Was not fixed in 1.32.3
Update: It seems to work now (patch 1.32.5) i have tested and both orange and purple camp give credit for me now. I can’t read in the patch notes why.