macOS Sierra 10.12.1, GeForce GTX 680MX 2048 MB
Broken: 2.78 (release)
Creating Bendy Bones when using centimetre scene scale causes very odd scaling.
Exact steps for others to reproduce the error
Open Blender, set scene units to centimetres
Create an armature (single bone), edit mode, subdivide twice.
Object Mode, got to Armature Tab and change to B-Bone.
The bones will get very long and thin.
If you do this without changing the units/scene scale, the b-bone is correct.