While creating shopping cart you may see the approver but after you submit , it does not go for approval also you cannot see the approver afterwards .
SAP Business ByDesign
You would have used the work distribution called "direct approver" In the approval process ,this work distribution has the below to be checked.
If the requestor, creator, or recipient is assigned as the direct approver, and if the approval process consists only of a single step involving direct approvers, then an approval task will not be created, and the shopping cart will be requested.
However the details given above is checked by system only after you submit the shopping cart thus approver is removed after you submit, unfortunately there is a limitation with this work distribution of shopping cart alone to remove approver before submitting the shopping cart and thus you see the approver while creating shopping cart.
approver disappeared in shopping cart, , KBA , AP-REQ-IR , Internal Request , Problem