I think OP is implying that time works like a film strip, so that if I’m five minutes behind you, I see where you were five minutes ago.
That’s the way time travel in Trek works. If you travel from Time B in the future to Time A in the past at a given place, you see the place as it was at that time, including the people who were there.
I think that rather being just shifted in time a la time travel, they were actually dealing with a flex in spacetime, like a curve in the road you can’t quite see around, but Diana could see their essence like light from the tail lights, as in your example.
In other words, they were caught in a time warp, again.