It is not clear how to reason about time because of Bell's inequality. The idea is that things do not have actual classical values of time or position in space until measured. [That was based on the Einstein Rosen thought experiment about polarization of light that shows either one of two things. Either action at a distance or things have no classical values of time until measured. [The experiment was done in the 1960's.] We know there is no action at a distance from GPS which depends on Relativity, so the second is true.]