I've wondered for years what happened to college-Shoko after her timeline ended. Knowing that life's memories just popped into JC-Shoko's head seems anticlimactic, but i guess it has to work this way since final-timeline Shoko canonically remembers all her future selves, something that's key to the University arc.
That last bit could be really awkward, given it means she has memories of several years of wedded bliss with Sakuta.
This is the one point I never could wrap my head around when I watched the movie. Sakuta is too good to a fault, and this showed how selfish he really was. Sure, he could feel good about saving someone else, but he never really cared about how the people he loved (Mai, his sister) would react to his death.
At least he eventually learned his lesson, but still never really sat well with me.