This happens to an unlucky streamer and all his gladiators and items disappeared. We watched what he did while playing and seen that he changed the name of the gladiator using comma and some other characters while changing gladiators name. Then this gets saved and because we use some of those in save game, the load game gets confused and breaks the game. Now this is fixed and you can use any character in name that you like and it will keep working. Like this for example: https://prnt.sc/1wqs8vv
Sorry for inconvenience. It was something that we did not predict but now it's solved.
Thank you!