Steps to Reproduce:
Make a linearGradient element that works for translated user coordinate systems with the default gradientUnits="objectBoundingBox".
Then try the linear gradient in a rotated user space.
The bottom three rotated rectangles of the image all show gradient fills, but the three rectangles are not identical.
The bottom three rectangles should be identical.
The leftmost bottom rectangle is correct but was done with gradientUnits="userSpaceOnUse".
The two rectangles to its right use objectBoundingBox and do not match. They do not have a white edge on the southeast.