  In disordered itinerant magnets with arbitrary symmetry of the order
parameter, the conventional quantum critical point between the ordered phase
and the paramagnetic Fermi-liquid (PMFL) is destroyed due to the formation of
an intervening cluster glass (CG) phase. In this Letter we discuss the quantum
critical behavior at the CG-PMFL transition for systems with continuous
symmetry. We show that fluctuations due to quantum Griffiths anomalies induce a
first-order transition from the PMFL at T=0, while at higher temperatures a
conventional continuous transition is restored. This behavior is a generic
consequence of enhanced non-Ohmic dissipation caused by a broad distribution of
energy scales within any quantum Griffiths phase in itinerant systems.
