Bug in workflow? Deleting approved OKR is allowed.

Client started using workflow with the following symptom:

• Setting: approval workflow is enabled and "prevent changes after OKRs are approved" is checked
• Situation: OKRs are "Approved" by a manager
• Problem:  Employee is still allowed to delete aproved OKR item

Do you have a practical experience with workflow?

Based on the definition described at https://learn.microsoft.com/en-us/viva/goals/approval-workflows our environment allows people deleting approved OKRs.

Can you share best practice?

Thank you

Roman