Druaga boss - How to open a door?

[Telep0rt0wnia]

Hello, I have a problem with reaching the Druaga boss - I have cleared everything, the entire 5th Wing, and when I am here in front of the boss's door, no creatures have appeared. I can't open the door, I'm at a loss.
I have some kind of rune with the sun, I got it somewhere, I don't remember where and I can't open the door anyway. I have all the memories too. Is this an error? How am I supposed to beat the game with the real ending now?

[Telep0rt0wnia]

I will add that there is a blue dot on the map meaning that I can enter there, but it is closed :c

[Telep0rt0wnia]

Ok, I'm very sorry for the inconvenience, because all I had to do was leave the winter area and enter again.
I'm super happy because this game is really great.

I'll leave this thread as a souvenir xD