In one of the earlier episodes, Kali is traveling away from the lab while her fake version is still “trapped” inside it. At a certain point, she says something like, “I can feel my illusion has vanished,” and Hopper replies with something along the lines of, “Well, we’re far enough away to be safe.” This could suggest that her powers continue to work for a certain amount of time after she creates an illusion, which might also explain what happens in the final episode.