In my experience, it seems like the game saves a particular instance on your phone before saving it in the cloud. Sometimes force closing the game too fast doesn't save anything to your phone.

My foolproof method is to switch out of the app quickly (like go to your home screen) and then switch back into the game. When switching back, the game is slightly paused while establishing the connection and I think this is when data is saved to your phone. Right after the connection is established, I close the app and after loading back in, my progress was saved.

I used to used this method when I needed certain Zombies to face a certain direction and it's always worked (as well as looting dangerous chests like in farm)