Stringent LDA PSP for Cu does not pass the test

[Vahid999]

The LDA (Perdew-Wang) PSP for copper called cu-sp-high.in shows large deviation in log derivatives for d- and f-states. I guess the f-state is less serious but is there a reason the d-state shows large discrepancy? Interestingly, trying to rectify the situation results in negative phonon frequencies for many q-points in the BZ. In its present state, all frequencies are positive.

Thank you,
Vahid