Hair simulation porblems in UE4.24.3

hi, I’m testing the hair simulation system in UE4.24.3. and I met a problem that i don’t know why.
When I abled the “Bind Groom to Skeletal Mesh”, then the hair color changed into gold, it should be dark brown.
Can anybody tell me what caused this change?

and one more thing:
When I apply the Niagara System into the hair, and it is totally out of the shape.
and I have no idea about this?
I really hope somebody can answer my question, thank you so much…