Collapsible self-closes in Firefox (not in Chrome)

[pmullot]

Collapsible closes itself whenever I press a key in input field in Firefox

I have an Angularjs SPA using materializeCss and this library. In this web, I have a collapsible containing some inputs. Whenever I hit a key inside one of these inputs in Firefox (54.0 ), the collapsible closes itself. In Chrome, it doesn't happend.

You can see the issue there:
jsFiddle