Invoice Approval Not Routing Properly

Summary: Our invoices approval rules routes to the Manager of the Invoice Header Requester, but for certain invoices, they are routed to the Manager of the Invoice Creator instead.

Content (please ensure you mask any confidential information):
Sample error scenario:
Emp X = Requester
Emp Y = EMP X's Manager
AP A = Invoice Creator
AP B = AP A's Manager

When Emp X is tagged as requester the invoice approval routes to the AP B instead to Emp Y.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):