Expense Report Status Directly changed from Pending Manager Approval to Ready For Payment

We've created a Vacation rule for one employee in order to transfer the approval Notifications to the next level manager/user. When the user A is submitted the report, the approval is went for B (On Vacation ) Vacation rule created for re-route the approval to C, and the C has approved the expense report. Once C Approve the report the Expense report status is directly changed to Ready for Payment Instead of Pending Payables.

Note: There is no issues with Expense report Audit rule.

Please share any info is available related to my request.

Thanks is Advance