I found a solution: once this light bulb appears over Lukan's head, and you have to lead him through some maps, just ignore this light bulb and go ahead into the map. It works like this, thanks Heaven. This light bulb keeps appearing over Lukan's head at different stages of the game ... and it's all about ignoring it and carrying on. Hope it helps all of you who, like me, thought they were stuck, but in fact, we can just go on
