this is what I don't get
I am assuming the movie is in a linear fashion- with the characters' present selves getting photos from their future selves and watching day by day how the story unfolds. Each night they replicate the scene to match the photo they received 24 hours prior, they then receive a new photo from their 24 hour future selves.
In this regard, the movie makes sense to me up until the point where we discover Callie's present self is sending messages to her past self. If Callie's present self sends messages to her past self, now we have three time lines- we have the future, present, and past- it seems to me that so long as Callie keeps sending messages to her past self to change the present, how can time move on?
When Finn was questioning her about the photos she had hidden in the drawer showing what appears to be an affair with Jasper, she seemed to be aware of this affair even though it didn't happen in the linear time line we are watching of their present selves, indicating that she remembers all of her past and present selves. If Callie's present self remembers events of her past self before she changed them with the messages she is sending to her present self, why can't the other characters remember?