EasyGamer: Don't get me wrong, I love you GoG guys and gals but....you did have that GoG-made article flaunting the modability of these recent Bethesda releases (Oblivion and Fallouts) on your frontpage. As such, and with this possibilty of moding these games, with or without GoG Galaxy, this issue was, for lack of better word, avoidable.
Regardless, if one is going to mod via Galaxy... it is the users responsibility to disable auto-updates as these can and most often will break mods.
EasyGamer: And, without wishing to escalate matters further (eh eh), the Galaxy created shortcut for Oblivion forces Galaxy to open itself first before actually starting the game, like games on Steam, as opposed to the other Galaxy games - that I'm aware of - where the shortcuts just open the games directly.
You can still play every game installed via Galaxy without Galaxy. GOG added this recently, I assume because they want to push people to use features like cloud save and/or to cut out support questions of people not realizing Galaxy has to be running for these features to work, etc. You can however manually create your own shortcuts to the exe file of the game and launch without Galaxy running as always.
The only change is to the shortcut itself, it now invokes Galaxy. They games themselves have not been touched.