I am experiencing the following situation: I am logged into an instance of Jenkins that supports multiple users and is configured such that, by default, they cannot trigger each others jobs. I have created a matrix job, checked the "Enable project-based security", added my account to the permissions matrix and checked all options, including the job build option, to give myself all permissions for my job. Now, I can manually trigger a build without a problem. However, when I try to trigger any build of my own job via the matrix-reloaded mechanism, I get a permission denied error message.
It seems this is because the matrix-reloaded plugin is not handling permissions in the same way that the normal manual build triggering mechanism does. When I go to the Jenkins global security settings and enable the job build permission for all users, only then will triggering a build via matrix-reloaded work. However, this defeats the point of a per-job authorisation strategy since now everyone on the system can trigger my jobs.
I suspect the fix to issue #16628 was not actually implemented correctly. My suggestion would be to check the permissions in the same way that the normal manual build triggering does. Ideally, using the same code.