We're using the Github OAuth plugin since a couple of days with the use repository permission flag activated.
This means Jenkins will look the user permissions through the Github permission on the repository of the looked item.
This works fine for all our regular jobs, but gives only READ/BUILD permissions on pipeline jobs.
I think the problem is that we don't use the Multibranch Pipeline plugins and thus fGithubRequireOrganizationMembershipACL.getRepositoryName fails to return anything meaningful.
Using the jenkins console, I could find that getRepositoryName throws a NullPointerException on those pipeline jobs.
I believe that the code should test for the presence of the BranchProperty before dereferencing it, and if this property doesn't exist, it should simply call getTypicalSCM() on the project.