Wrong Urlencoding when Switching Branch in Graphs / Contributers

Summary
We are using gitflow and are naming our featurebranches like feature/#ISSUENUMBER.
If I want to switch to some of those branches in the Graphs view - i get a HTTP 404 Error.
Gitlab redirects to https://SERVER/GROUP/PROJECT/refs/switch?utf8=✓&destination=graphs&ref=feature%2F%252310 but it should redirect to https://SERVER/GROUP/PROJECT/refs/switch?utf8=✓&destination=graphs&ref=feature%2F%2310 or https://SERVER/GROUP/PROJECT/graphs/feature%2F%2310 which are both working.

Also, like in Issue #20759 (closed), i am unable to switch to those branches in the Commit view.

Reproduce
Just create a Branch like feature/#Number and try to check out the Graphs view.

Expected Results
Correct redirection to the above mentioned URIs.

Server Environments
GitLab 8.11.0
GitLab Shell 3.4.0
GitLab Workhorse 0.7.8
GitLab API v3
Git 2.7.4
Ruby 2.3.1p112
Rails 4.2.7.1
PostgreSQL 9.2.18