// this is just one file for example
<link rel="stylesheet" type="text/css" href="/app_dev.php/css/ab72c13_main_1.css"/>
I finally found the problem, with the help of @cordoval.
I had two files that configured assetic: use_controller and one of the was overriding the other one with true.
So the solution to this problem is to set assetic: use_controller : false and use assetic:dump --watch to automatically dump the assetic in case you don't want to do that every time you modify a css/js file.