Error in the documentation of the pressure velocity coupling within the extended Code guide
Under this link you can see the following:
Au+H=-grad(p)
u=H/A-grad(p)/A
It is hence obviously incorrect. The sign of H hasn't changed. The correct definition is
Au=H-grad(p)
u=H/A-grad(p)/A
This also makes the definition of M[u] not correct.