For anyone not wanting to visit the cesspit, this is what an official, verified GOG account replied:

I want to briefly address the discussion as a GOG representative. The Sowilo rune is part of my cultural and historical heritage. As a Pole, I am fully aware of both its history and the sensitivities surrounding it. Its use in this promotion was intended solely as a reference to the sun, which is central to the game being promoted.

What was displayed in several devices as doppelrune is out of our control. ᛋ was displayed as ϟ on several devices. We should pay more attention to checking it on a different systems and devices. I also recognize that placing two such runes next to each other could create an unfortunate association with symbols used by the Nazi regime. This was noticed before distribution, and out of respect for local sensitivities, the material was not sent to the German community.

At the same time, I do not believe that symbols with a history spanning more than a thousand years should be defined solely by their misuse in the modern history. Allowing that would mean accepting that those who corrupted these symbols now own their meaning.

As a Pole, I have every reason to treat this history with seriousness and respect. Precisely because of that, I reject any suggestion that this promotion carried an extremist message. It did not. It was a reference to the historical symbol of the sun, nothing more.