  Emergent excitation continua in frustrated magnets are a fingerprint of
fractionalization, characteristic of quantum spin-liquid states. Recent
evidence from Raman scattering for a coupling between such continua and lattice
degrees of freedom in putative Kitaev magnets [1-6] may provide insight into
the nature of the fractionalized quasiparticles. Here we study the
renormalization of optical phonons coupled to the underlying $\mathbb{Z}_{2}$
quantum spin-liquid. We show that phonon line-shapes acquire an asymmetry,
observable in light scattering, and originating from two distinct sources,
namely the dispersion of the Majorana continuum and the Fano effect. Moreover,
we find that the phonon life-times increase with increasing temperature due to
thermal blocking of available phase space. Finally, in contrast to low-energy
probes, optical phonon renormalization is rather insensitive to thermally
excited gauge fluxes and barely susceptible to external magnetic fields.
