  The strong cosmic censorship conjecture proposes that starting from generic
initial data on some Cauchy surface, the solutions of the Einstein equation
should not be extendable across the boundary of the domain of dependence of
that surface. For the case of the Reissner-Nordstr\"om-de Sitter spacetime this
means that any perturbation should blow up sufficiently badly when approaching
this boundary, called the Cauchy horizon. However, recent results indicate that
for highly charged black holes classical scalar perturbations allow for a
violation of strong cosmic censorship. In a recent paper arXiv:1912.06047, two
of us have argued that quantum effects will restore censorship for generic
values of the black hole parameters. But, due to practical limitations, the
precise form of the divergence was only calculated for a small number of
parameters. Here we perform a thorough parameter scan using an alternative,
more efficient semi-analytic method. Our analysis confirms arXiv:1912.06047 in
the sense that the quantum stress tensor is found to diverge badly generically.
However, the sign of the divergence can be changed by changing the mass of the
field or the spacetime parameters, leading to a drastically different type of
singularity on the Cauchy horizon.
