When updating an issue from a custom domain, it is posted to a wrong url (BB-6343)

When updating an issue from a custom domain the form is posted to a wrong url (look at attachment). The url includes the repository owner name, when it should not since this is already included in the custom domain.

e.g. mycustom.com/mycustom/repositoryname/issue-edit/id
should be:
mycustom.com/repositoryname/issue-edit/id