The bug has now been fastened, and there is a ticket for it on Rockstar’s assist website. This is the complete textual content of it.
Query: Why can’t I set GTAV for PC to Offline Mode now that I’ve up to date to the Rockstar Video games Launcher?
Reply: With a view to Play GTAV in Offline Mode, gamers might want to:
Run the Rockstar Video games Launcher and replace it with the newest model
Sign up to the Rockstar Video games Launcher
Replace GTAV to the newest model
Launch GTAV by way of the Rockstar Video games Launcher whereas on-line
So there you go. You will have to be on-line to launch it the primary time, however, after that you must be capable of play in offline mode once more.