Motion blur difference between render delegate and procedural

[cpichard]

Description from Pablo Garcia:
Hello,
I’ve found a problem with the velocity motion blur on viewport (hydra delegate) when we render geometry, curves or points (with instances works fine), it looks like it’s inverting the velocity attribute as can be seen in the attached image, with Kick it works fine. This is a big issue if we need to render something with a shutter not centered on frame or when we want to fake the motion blur of particles.
it's not a regression though, we didn't realize about it as were normally using centered on frame motion blur.
I attach some usda scenes that reproduce the problem.
inverted_motion_blur.zip