  We investigate the late-time cosmological dynamics in a simple case of
explicit spacetime-symmetry breaking. By expanding in a small symmetry-breaking
coefficient we are able to write the Friedmann equations as $\Lambda$CDM +
dynamical dark energy, which we show contains logarithmic dependence of the
scale factor. We find that the dark energy equation of state displays
divergencies and phantom behaviour for certain values of the symmetry-breaking
coefficient, where the NEC is also broken. We discuss the adiabatic sound speed
of dark energy and compare the model to current constraints using the
Chevallier-Polarski-Linder parametrisation. Remarkably, although the
constraints on the same symmetry-breaking coefficient from e.g.
gravitational-wave propagation are orders of magnitude stronger than what we
obtain in this paper, we are able to cut those constraints, which are more or
less symmetric around zero, in half by showing that same coefficient must be
negative (or zero) if one wishes to keep the NEC intact.
