Last week, this notification popped up in the game lobby: -

What it meant is that your carefully crafted deck is now marred, especially if you are a newbie and relies much of the gameplay on core cards. I guess the 'Core Set Refresh had inflicted much hassle on the GU Community since many of the players relies on Core cards, not only poor noobs like me.
You'll have to re-plan all your decks if you are a poor noob like me! It happened that all of my decks were no longer complete, some with 6 or 7 cards missing.
Why GU had refreshed the cards
Theofficial reason it happened is because GU thought that the balance of their cards was wrong and they are now repentant. Did they change the cards in order to make the game fairer to all users? The answer is negative. The game is fair, but it is fairer to some.
Basically, the 'refresh' has undermined the poor noobs' ability to use some of the card combinations to defend themselves against powerful opponents.
Also, the 70 new cards means new products to sell, for the GU company. Profit, profit, profit!
Who said Immutable X was Immutable?
Poor Man's Example
For example, the 'Portable Fortress' had shifted domains from a neutral card to a Magic card. So, when you play as the 'god' of Nature, it could no longer be used in tandem with the 'Aspect of the Axolotl' (Nature), which gives +6 HP Regen to the Fortress at the end of your turn. I have discovered this poor man's combination and had luckily used once in my previous battles. Of course, this +6 Regen Portable Fortress had eventually been cracked down in the battle by the opponent.
By moving 'Portable Fortress' to the Magic domain, it is oh so obvious that they are wanting to follow up and tackle these so-called loopholes which were improvised by the poor noobs.
The colour of the triangle on the top left represents the domain.
Grey: Neutral (can be played by any 'god')
Blue: Magic (only by the 'god' of Magic)
Green: Nature (only by the 'god' of Nature)

Fun fact
An axolotl (/ˈæksəlɒtəl/ or ACK-suh-LAH-tuhl) is a member of the tiger salamander as pictured below.

Axolotl (Ambystoma mexicanum) - Wildtype | A young wildtype … | Flickr ©John P. Clare
No one on Reddit mentioned this 'Refresh'!
A week ago, I googled 'Gods Unchained Core Set Refresh' and nothing came up on Reddit. So strange.
Basically, GU bullied their own players to sell their products. They only told you that they changed your cards after they did it. No warning nor signs before they recklessly change your property. They didn't even ask.
So what do you think about this Core Set Refresh? Do you agree that these Refreshes aim at stripping poor noobs? Let me know in the comments!