All fields, including those set to "Not Visible" or "Read Only", are displayed when there is an error saving Apply Planned Time.
SAP SuccessFactors Employee Central
Reproducing the Issue
When there is an error during the save of apply planned time, all fields are visible, even those that are set to "Not Visible".
This is currently planned to be fixed in 2H 2022 release.
WEF-26352, KI2022, Apply Planned Time, Time Off, Error, Visible Fields, Incorrect Fields, Hidden Fields, Read Only Fields , KBA , LOD-SF-EC-TIM-ABS , Absence error's - Calculations, Deductions, TT&ET , LOD-SF-EC-TIM , Time Off , Known Error