  In this work, we investigate the resonant contributions of $K_0^*(1430)$ and
$K_0^*(1950)$ in the three-body $B_{(s)}\to D_{(s)}K\pi$ within the
perturbative QCD approach. The form factor $F_{k\pi}(s)$ are adopted to
describe the nonperturbative dynamics of the S-wave $K\pi$ system. The
branching ratios of all concerned decays are calculated and predicted to be in
the order of $10^{-10}$ to $10^{-5}$. The ratio $R$ of branching fractions
between $B^0\to \bar{D}^0 K_0^{*0}(1430) \to \bar{D}^0K^+\pi^-$ and $B_s^0 \to
\bar{D}^0 \bar{K}_0^{*0}(1430)\to \bar{D}^0K^-\pi^+$ are predicted to be
0.0552, which implies the discrepancy for the LHCb measurements. We expect that
the predictions in this work can be tested by the future experiments,
especially, to resolve $R$ ratio discrepancy.
