  We show that the stress tensor of a real scalar quantum field on
Reissner-Nordstr{\"o}m-de Sitter spacetime exhibits correlations over
macroscopic distances near the Cauchy horizon. These diverge as the Cauchy
horizon is approached and are universal, i.e., state-independent. This signals
a breakdown of the semi-classical approximation near the Cauchy horizon. We
also investigate the effect of turning on a charge of the scalar field and
consider the correlation of the stress tensor between the two poles of the
Cauchy horizon of Kerr-de Sitter spacetime.
