In routing.yml 3 routes were using invalid service name:

studioui_getfriendlyurl:     path: /studio/content/locations/{locationPath}/friendlyurl
    defaults:         _controller: ez_studioui.studio:getFriendlyUrlAction
    methods: [GET]
    requirements:         locationPath: "[0-9/]+"

ez_studioui.studio which correctly is registered as ez_studioui.studio.

For some reason Symfony 2.x is ignoring underscores so that mistake had no impact. The problem is ocurring on Symfony 3.x.