when using 0 tick pulses to move observers, if you 0 tick an observer to a place retract it 3gt later it will do as it is supposed to be doing. however, when you 0 tick another observer where the previous observer used to be the second observer power 1 gt early. in the video I use a piston to visualize the difference because the piston is supposed to fire twice. I have tested this in 1.16.4 and 1.18.1