Manager field in user profile

Hi everyone. Is there either a known bug or a configuration that would cause a Manager to be removed from a user profile under Company>People? We are on Ramp Plus. I have had a couple of instances where an approval will come to me as an admin, which should only be happening on very rare occasions. And when I look into why admin approval is needed, the manager is not defined in the employee profile. We are preparing for our full companywide rollout, and I want to make sure I’m not configuring something to cause this to happen. I only have 9 users currently. I appreciate any feedback you may have.