I just heard about this. My brother and 3 of his friends purchased Hearts of Iron 4 during the Sale. Now they all can claim a free base Paradox game or 2 DLCs. If you bought a Paradox game between May 17 and today you can claim the free game or refund it. Except if you used USD currency they not changed the prices in those countries, mostly in Europe.
Heard this before the sale. Regretfully, some companies increased their prices a month before the sale because of greed. In such countries as Ukraine and Russia the sales of Paradox games dropped significantly and they admitted this. It’s a shame that developers don’t want to make a profit from new games, but prefer to leech from existing games and series.