I don't know why but when I roll a 20 it sometimes says critical failure which doesn't make any sense to me. I thought a natural 20 was a critical success.?.?. Has anyone else come across this? Is this a bug?
Are you using the fancy red dice? If so the 20 and the 1 both have special faces. I thought the same thing at first but figured it out. If not using those dice then I don't know.