I am seeking a scientific explanation behind this phenomenon which is unprecedented to me.

I was performing a piece on a music keyboard. I was filming it with my phone’s camera as well as recording the sound via the keyboard’s built-in tool.

After reviewing the recordings, the film and the keyboard’s recording simultaneously stop emitting sound at the same exact millisecond.

This infuriated me quite a lot, but now it intrigues me. What happened there? I am willing ro provide more information if needed.