https://streamable.com/uv05rm

You see the sage running across to the right side but then see the sage peeking from the left side? I don't get it?

The clip is a lil bit older and also not my own clip but rather a clip my friend made, but it has been haunting me for a while and want an explanation, can someone please tell me wtf is going on in this clip? It might be lag but honestly im not sure and idk if it is, if anyone has any insight as to what the fuck is going on then please feel free to tell me i would love to know