In (60) of VW the branch cut was wrong (also in
Mathematica). I misunderstood the meaning of

if (a.back() > 0) {
    new_pending_integrals.push_back(-scale);
    result += I*Pi;
} else {
    new_pending_integrals.push_back(scale);
    result -= I*Pi;
}

in GiNaC