Update
Old
Duplciate the metahuman BP as backup
Open BP → Class Setting
Parent Class choose 3rdperson BP or the source retargeter
Drag the Root (in update versoin clip) body (in old version) and its sub components child under the 3rd person mesh
Open Use Live Target Mode variable, tick its default value
Complie, should see the metahuman idle
invisible the 3rd person mesh and
UE5.1 may need different steps if the character don’t move in simulation
Extra things to fix in 3rd person BP and metahuman BP