With two flex divs inside a flexbox, the first div containing long text, the content of the second div overflows the flexbox even when wrapping the first text would allow space for the second to be displayed inside the flexbox. Example here, when resizing screen to for example 600px wide : https://codepen.io/SophieWeb/pen/VKZQjR
Ok I just misunderstood the specification. Apologies for filing this as a bug, a flex-shrink of 0 on the second div solves it.