Elevation is weird on GradientCard

[bernaferrari]

elevation: 1.0,
shadowColor: Colors.black,

GradientCard

Default Card

[✓] Flutter (Channel dev, v1.7.11, on Mac OS X 10.14.5 18F132)

[bluemix]

still got the same problem?
can you show me a code snippet how you're using it?