  In a recent study [NVdB2017] of algebraically special Einstein-Maxwell fields
it was shown that, for non-zero cosmological constant, non-aligned solutions
cannot have a geodesic and shearfree multiple Debever-Penrose vector k. When
$\Lambda=0$ such solutions do exist and can be classified, after fixing the
null-tetrad such that $\Psi_0 = \Psi_1 = \Phi_1 = 0$ and $\Phi_0 = 1$,
according to whether the Newman-Penrose coefficient $\pi$ is 0 or not. The
family $\pi = 0$ contains the Griffiths solutions (Griffiths 1986), with as
sub-families the Cahen-Spelkens, Cahen-Leroy and Szekeres metrics. It was
claimed in [Griffiths 1986] and repeated in [NVdB2017] that for $\pi = 0$ both
null-rays k and l are non-twisting: while it is certainly true that $\mu \Im
(\rho) = 0$, the case $\mu = 0$ appears to have been overlooked. A family of
solutions is presented in which k is twisting but non-expanding.
