SSometimes if I switch to a different app for a few seconds mid-level to answer an important call/text it will reload the whole game, taking a life, ending my streak, etc. This just happened to me. I was 80% of the way through a top tier Candy Royale with 116 gold on the line and this happend. Got bounced out of the challenge, very frustrating. The game should save where you are in a level in case of a crash or the app is closed. I swear its built-in for this to happen. It doesn't happen every time you leave and come back, but seems to when important things are happening.