Sorry to hear that, Ami! We've made a ton of progress on the "Boot-to-lobby" issue! We've identified the issue and it's already being worked on, unfortunately I cannot give an estimate on when this will be fixed since it's a very complex bug, but we're making strides!
Whenever your friends crash, please ask them to NOT open the game again, then go to their %AppData% folder (type that on windows explorer search bar). Go to AppData/LocalLow/BitCake Studio/Atomic Picnic. There will be a player.log file, if you could send that file to us it would be great, you can reach me or [Dev]Bill on our Discord for this.