CePeU: That is sad to hear and maybe I need to buy it on steam then. But if that is the case it should be removed from the specials offer banner which now seems to be the case. Thanks for the information - sdaly I was of the impression that GOG will hold the offer as long as steam does.
HunchBluntley: Why would that be the case? Different stores have different deals and plans regarding what goes on sale when, and for how long. Even with Steam being the elephant in the room which no one can ignore, not
everything their competitors do completely revolves around that store and what
they do.
Aside from that, the store page of every discounted game on GOG has a bit right above the price which gives the date and time when the discount is supposed to end. This is a nice feature (and one which GOG didn't have for most of its existence), so take advantage of it! :)
What is strange is that BG3 Facebook page says the game participates in Summer sale on GOG which is misleading as well