  A field-theory approach is used to investigate the ''spin-glass effects'' on
the critical behaviour of systems with weak temperature-like quenched disorder.
The renormalization group (RG) analysis of the effective Hamiltonian of a model
with replica symmetry breaking (RSB) potentials of a general type is carried
out in the two-loop approximation. The fixed-point (FP) stability, recently
found within the one-step RSB RG treatment, is further explored in terms of
replicon eigenvalues. We find that the traditional FPs, which are usually
considered to describe the disorder-induced universal critical behaviour,
remain stable when the continuous RSB modes are taken into account.
