Hi there @DiagaDumah,
A Video would be very helpful. But, the behavior doesnt sound like an issue the Master Pose Component, it sounds like an issue with Base Skeleton. If you hide base skeleton it will stop animating. A Blank Skeletal Mesh, suggests there is no skeleton which could produce a similar result. You can use the Console Command ‘Show Bones’ to see the skeleton bones at run time. I recommend using a skeleton mesh with geometry as the base mesh until you resolve the issue.