That's correct, the crash is triggered when Lop reaches LV5 and attempts to learn the "Health Shower" ability. This is a typo and the ability is actually named "Life Shower" so the game crashes when it fails to look up the ability details. This normally happens after defeating a tentacle, but can happen any time the party reaches LV5.
Thanks for the comment and the kind feedback by the way, I'll upload the fixed version after the voting period ends.