That's a known bug with dozens (over a hundred?) posts about it in this thread. I don't know which version you are playing - either v0.82.4a or b ... or v0.85.1a. What's strange is that unless a person records their playthrough from the first moment to show all their choices to get to the bug, it may remain in there for a long time. Developers haven't mentioned being able to recreate the bug and several folks I know who have attempted, haven't been able to do so, either. I've failed to get the bug whenever I have tried.
You should check to make sure you have purchased all three cameras and be sure they are still in your inventory before going into the house. If you have waited a too long in game days (and possibly have done other quests that involve inventory items) after purchasing the cameras, it may cause an inventory bug for the quest.
I would recommend going back to the save before you bought everything in the store for the quest. Buy everything and then immediately go do the quest. When you do it, do it in the same order you did it in the video. Oh, and don't CTRL/Skip through the dialogue with Gerda just before. Just click through, normally.