Spot the mistake?

I’m really pleased with my latest YouTube video…. except for one thing! Watch closely and you’ll soon spot the error. And now I have a dilemma – do I take it down and redo it, or do I leave it up on YouTube and see how many people report my mistake back to me?

Please share if you like the video (or the mistake!

Here’s a direct link if you want to copy it: https://youtu.be/Eh-ZPvpgCzw