At the end of yhe video you see a blue and a red axis at the left of the screen and the moving blue nowline of the moving frame at the right of the screen. In the video the time at x=0 (red line) and x'=0 (blue line) stay the same, This cannot be because t'= t/γ.

Each of those 0's in your statement [x=0 (red line) and x’=0 (blue line)] corresponds to the origin of each coordinate system - which of course always stay as they are, at constant speed. Your notion of t' is actually one that's illustrated by the moving "nowline".

Worldlines (spacetime trajectories), events, and causality. Wow. In history as a person of Polish heritage we wonder why 19 million people in Polands borders were erradicated the last century. Minkowski was the workhorse, Einstein the face. Jewish culture mobilizes media better. Nazislam can t tell us apart. https://phys.libretexts.org/Courses/University_of_California_Davis/UCD%3A_Physics_9HB__Special_Relativity_and_Thermal_Statistical_Physics/2%3A_Kinematics_and_Dynamics/2.1%3A_Spacetime_Diagrams

Marius is right. There is a mistake in the video. Time in the origing of the moving reference is not taking in account time dilation. I already saw the same mistake in previous lessons were this demonstration was also used