I have two jobs, Folder/job1 and Folder/job2. A promotion process is defined on Folder/job1 which requires manual approval by User; the promotion process specifies 'Trigger/call builds on other projects' to run Folder/job2 with the 'block until finished' option selected.
User is a global administrator with all permissions granted, but Folder/job2 has project-based security which overrides the global matrix and specifies that User does not have the 'build' permission, i.e. the checkbox is clear. When visiting the job page for Folder/job2, User is not given an option to build. However, if User clicks the promote button on Folder/job1, Folder/job2 builds.
I think that in this scenario the promotion process should fail.