Your issue is listed in the top sticky post, though it is not clear yet when a fix will be available:
What appears to work at least for some people is to remove the problem cards from the deck, then add the non-golden version. Save the deck. Edit again, repeat with the golden version. Doing it twice like that would “unlock” the regular, then the golden version. However, this workaround will have to be re-done the next time you log in.
Also, as you have noticed, the issue is when you have a regular and a golden copy of the same card in the deck. For those who still have two identical copies (regular or golden), using those instead will avoid the issue for the time being.