Please advise about massive game bug (Forest's Fury)

[Silver]

So as per the purchase records I keep, I bought this game many years ago (September 2011), and in April 2012 I bought Deck Pack 2 and Deck Pack 3. I had started playing the game before that (without DLC 2 and 3) and unlocked some decks, don't remember how many, probably beat the main campaign and unlocked the original 10 or so decks.

In the meanwhile, I have continued to play the game and unlocked all cards for 17 out of 19 decks. The only decks I have unlocked 0 cards for is March to War, and Forest's Fury.

Now I have heard a lot of talk that Forest's Fury corrupts your save and resets all deck unlock progress - is this going to happen if I start playing Forest's Fury and unlock the first card? Or when will the bug trigger? Because so far it has not triggered for me (I have played AGAINST Forest's Fury many times and my save still works in terms of remembering my unlocked cards); I have cloud sync enabled.

Is there any way of solving this issue without starting over again?