Originally Posted by SiriusFun
GOG builds offline installer when they get it from Larian. Is not like Larian does not have installers, and GOG is building from scratch. Larian has his part to "blame" too.And I agree that waiting a day, as you suggested, will suffice.
Larian has absolutely nothing to do with GOG's offline installers. Larian supplies the game build to GOG just as they do to Steam. Once it's verified, it's pushed through Galaxy to users very similar to how it is on Steam. GOG has to take the new build and make the offline patch. This takes extra time, which is why it's usually a day or so later than when Galaxy and Steam get it.