PPLNS with job declaration

Given a window with one slice. Given that slice contains 10 shares, 0…10.

Client A requests shares 1,3,5,7. Pool provides 1,3,5,7

Client B requests shares 2,4,6,8. Pool provides 2,4,5,8, mislabeling share 5 as 6

How does Client B know they were deceived? Assuming share 6 and share 5 are not shares they themselves submitted.