We compute the ${\Lambda }_b\to \Lambda$ transition form factors using light-cone sum rules based on $\Lambda$-baryon distribution amplitudes, including contributions up to twist–6. The analysis is performed for pseudoscalar, vector, and axial-vector $b\to s$ currents and for different choices of the ${\Lambda }_b$ interpolating current. A central aspect of the study is the explicit inclusion of the negative-parity ${\Lambda }_b^{*}$ state in the hadronic dispersion relation. Suitable linear combinations of invariant amplitudes are constructed to eliminate the ${\Lambda }_b^{*}$ pole contribution at the level of the sum rules. All three interpolating currents lead to numerically stable sum rules in the adopted working windows. The pseudoscalar current gives the closest agreement with the expected EOM and heavy quark symmetry relations at the level of the central values, while the present leading-order uncertainties do not allow a definitive discrimination among the three currents. The resulting helicity form factors are parametrised using a $z$-expansion and, for the pseudoscalar current, are combined with lattice-QCD tensor form factors to illustrate the low-$q^2$ differential branching fraction in ${\Lambda }_b\to \Lambda {\ell }^{+}{\ell }^{-}$.