Reason for creating Absence Orphan Record and FORFT

Hi Experts!

We would like to understand why Absence Orphan and FORFT records are creating in OC?

End user received below error when they trying to submit absence in OC, and once if we delete the impacted users FORFT or Orphan records then user can able to submit absences.

However, we are trying to understand the cause of creating Orphan and FORFT records in OC. What is the exact reason for creating these kind of Orphan and FORFT records ?

Regards,
Boopathi