Path tracing with some Metahumans is not working UE5

Hi, in UE5 stable release using path tracer with some metahumans (such as Vivian) in not working - path tracing seems not to converge, a lot of noise everywhere and no progress…any advice?
The issue seems to be connected to hair - disabling “Enable Simulation” in the groom asset soves the issue (but we loose the simulations…)
thank you!!