We have projects in JSM for different departmsnts; HR, IT, Finance etc. We have recently implemented a process in the HR project that creates tickets in other departments and links them.
However, unless you are an administrator who can see all projects, or an agent in all the related projects, the linked issues are not visible.
I've ensured the Linked Issues field is on all screens.
I've even tried giving Linked Issue permissions on projects. This allows the creation of a link, but the link is not visible after creation.
For obvious reasons I do not want to give all agents browse permissions on other projects.
I have noticed that linked issues for a Jira project do show even if there are no permissions for that project.