Premium questlines usually only have about roughly 5 tasks, just keep brockman running at the same time as arnie and you will be fine
CBG also triggers one part of the quest line.
The quest just seemed to have ended abruptly with Kent going back to his job after the viral phenomenon ran dry... I guess that was the end then. I would like it if after every questline a little pop up box came up and said "You've completed this story" or something. Otherwise I always check every character is off task to find out if the quest is still going.
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