Jira integration - issues link broken in projects

Context

We are currently using gitlab- 8.14.0-ee and jira 7.2.5

Summary

No css/js loaded on with external issues trackers when clicking on issues link. Gitlab and jira are on the same host, accessed via sub-directories (ie. https://host/gitlab and https://host/jira)

Steps to reproduce

  • Set up correctly jira integration in a project
  • Click the issues link in that project (or any link refering to Jira, such as links to issues in commit messages)

Expected behavior

We should be redirected to jira's page, including css and javascripts

Actual behavior

Jira's page is loaded but not including jira's css/js (we got gitlab's one instead), ending with an inconsistent display.

Relevant logs and/or screenshots

gitlab_jira You can note that the url is still gitlab's instead of jira's one.

Other

It works as expected if you're in the graph page of a project, all others pages seems to have the bugged behaviour.