Candidates cannot open the URL for internal job posting when they are not logged in
SuccessFactors Recruiting Management (RCM) - All versions
Please be aware that this is an expected behavior, since this link is for internal posted job, only internal candidates will be able to view this job.
The way that the system can control this is by opening the link only for the users that are logged in the system.
Otherwise, any other person that is not a part of your company would be able to view internal vacancies.
KBA , LOD-SF-RCM-JOB , Job Postings & Requisitions , How To