For some reason on mobile it stacks instead of replacing? I checked and the interactions are exactly the same. The only difference is that photo chooser in mobile is centered bottom instead of center of the screen like desktop.
This is because prototyping behavior is unique to each design, so it’s hard to determine if there’s a bug is causing problems, or if this can be adjusted to work as you expect. From what I can see right now, you may be running into some existing issues, but I can’t be entirely sure on my end.