I couldn't get the app to work on my phone, but from that video it looks like you might have made the cells update one-at-a-time in reading order, whereas in Conway's Game of Life the board is supposed to update all at once.

You fix this by having one 2d array to store the current state of the board, and then you have a second array in which you calculate what each cell is going to be on the next generation. Once you've calculated all the new cells you replace the first array with the second.

This is such a classic mistake that we even have a name for it: NaiveLife (https://conwaylife.com/wiki/Naive).