PO is lasting too much to change to "approved" status even when approved date is already populated

Hello Oracle Support Community,

I am asking for help to know why some POs are lasting too much to change to "approved" status even when approved date is already populated? something here is not synchronized, for example, approved date = '04-MAY-2018'  Approval status = 'In process', after more than 3 days it changes to Approval status = 'Approved' , I do not have any idea where is the problem.

I would appreciate any thought.

Thank you very much,

Best Regards