Every finished campaign give Epic card so lots more Epic cards now. And I think there is a bug to not let you summon cards for gold, but there are small bugs every update and get fixed after few days.
What do you mean "not to let you summon cards for gold..."
After update I have no problem with exchanging cards on the Shop tab - ie
1/10 random Cards for 100/1000 gold I dont. I get just this. But i use web version so, ...:

First levels give little Gold anyway so I am fine till will get fixed.