I'm the one that posted the video of the bugged Magic Lamp quest. I went back just now to the savefile I kept before I did the quest and might have found what makes this quest bugged. I'm convinced that we should be able to examine the statues before examining the door because Geralt says something about the statues if you examine them before the cutscene ("Really similar these statues"). You can do this by quickly running over to a statue and examine it before the cutscene with Keira starts. However, since the quests updates right after you examine the door there is no way for the game to include that you examined the statue thus making it think you didn't do it.(?)
I posted a video of my findings, but since I can't post links you can use the video link in the first post and check my latest video. It's titled: The Witcher 3: Wild Hunt - Magic Lamp (Objective Bug) pt.2
(or if someone could post the link here that would be great!)