Thread:Elledy92/@comment-26838855-20190425183005/@comment-26838855-20190427140710

Again, it's difficult to work out how they would return each stone but actually, it seems that the logistics of returning them don't matter so long as you just slip the stones back into their point in the timeline.

As for the Quantum Realm, I'm assuming he got stuck in a time vortex. They've discussed before about time being weird in the Quantum Realm. Janet stayed safe and aged normally, Scott got caught in a time vortex of some kind with time dilation.