iOS app in background occasionally loses progress

Hey devs! I’m loving Siralim 3 on mobile (have Android, but mostly playing on iOS). I ran into an issue with iOS the mobile app when I switch the app to the background when I’m 1/2 through a level (going to sleep, or just need to use the phone). Occasionally when I resume the game, I’ll have to continue from the main screen where I’m forced to restart in Nex, and all of my progress from the previous session was lost. Is this a known issue? Is there any way this could be fixed? Maybe just save the game’s state when the app switches from active to background?