"Jenkins URL for icon in Pull Request" Option Not Functioning.

I tried to give some customized URL in option "**Jenkins URL for icon in Pull Request**" for making the respective URL as the hyperlink/reference of the Image/Icon, But irrespective of configuration, the Image/Icon referencing same Jenkins URL always.

**Plugin Name:** GitHub Pull Request Coverage Status
**The Icon referencing URL currently:** http://jenkins_url/repo_name/$build_number/
**Required Icon referencing URL is:** http://jenkins_url/repo_name/$build_number/custom/

By passing the value **http://jenkins_url/repo_name/$build_number/custom/** in the option "**Jenkins URL for icon in Pull Request"** should work, but it's not actually working as expected.

It seems there is a **bug** in the plugin, please suggest how we can achieve our requirement here.