Thanks for reaching out, and I agreed this is not the behavior documented in defect # CSCuy64732. can you please create a TAC case so we can investigate this issue and provide resolution.
IP spoofing is not required to function WCCP, and will work just fine without it. If you do like to configure WCCP with the IP Spoofing and having issues, Please create a TAC case so we can help you quickly.
Thanks for reaching out, Can you please open a TAC case so we can further investigate. recently we have filed defect # https://bst.cloudapps.cisco.com/bugsearch/bug/CSCuy64732 effect S170 performance running 9.0.1-162 build.
We will be able to ...