Steps to reproduce:

symfony new symfony-app 3.2.0-RC2
cd symfony-app
bin/console s:start
open http://127.0.0.1:8000
open http://127.0.0.1:8000/_profiler/{token}?panel=router

The exception:

An exception has been thrown during the rendering of a template ("Notice: Undefined offset: 1") in @WebProfiler/Router/panel.html.twig at line 20.

And the ContextErrorException points to vendor/symfony/symfony/src/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php:280.