Used in reference to video games, when the gameplay cuts to a video that is unskippable, so you are forced to sit and watch it. Cutscenes can happen in real life when an event or conversation occurs at a time when it is inconvenient for you, or when you are trying to do something else. A cutscene is unskippable, and forces you to perform a certain task to progress in your day.
My bad bro, I got stuck in a cutscene. My mom made me do dishes before I left. Totally unskippable too.