If you create a sphere component as part of a BP, it has 3 values for the scaling, X, Y, and Z. While it lets you enter in three different values, but it only uses one of those values to set the radius (the smallest of the 3.)
Now I’m not sure if there is a bug because it won’t let you make non-perfect spheres, or there is a bug where the 3 values are not locked together. There is a lock icon at the end of scale that should be locked IMHO if the engine only supports perfect spheres. As it stands it’s just confusing because it ignores 2 of the 3 fields with no explanation why this is. At the very least there should be a tool tip that explains only perfect spheres are supported if that is indeed the case here.