Issue: I have permissions to edit items generally, but I am unable to edit any field for one or some specific items, why?
Resolution: Update the items approved status or update your permissions to be able to Edit after Approved.
To confirm this is the reason you are unable to edit this item navigate to the item in question and locate the Other Details tab within the item editor.
You will see the user that approved the item listed. To make this item editable by other users the approved user can either un-check the box, or permissions can be increased to Edit After Approved. Click Here for more information on employee permissions. If this box is unchecked and you are still unable to edit reach out to support.