There is currently a bug with the autolayout and the ‘‘fill container’’ property that seems to be related to the number of objects inside an autolayout group and the width value of a fixed object within it.
A bit hard to explain by text but all the details are available here in this demo and you can play around by duplicating some objects inside the auto layout groups you will see what I mean, it’s a bit special and it broke some of my components as well.
I’m pretty 100% sure it is a bug and not designed to work like this using ‘‘fill container’’ properties within an auto layout group :