After checking your project file:
Somehow I’ve managed to set the punch out marker to infinity
This remark puzzled me originally, but I think it is due to a misunderstanding. You have disabled punch-out in the transport toolbar, which means that Podium will display the punch-bar in the timeline indeed as extending into infinity. I repeat: this is not a bug 🙂
I did not manage to make your arrangement crash. I’m thinking it could be related to the plugins you are using. Try disabling the “activate power when opening arrangement editor” option in preferences. If it is a plugin that is to blame, then that will allow you to open the arrangement editor and mess around with the tracks to try to determine what causes the crash.