Vray Velocity - correct settings for Nuke and Frame Edges

[chronopsis]

Working on compositing a simple motion blur test in Nuke, rendered in Vray with a velocity pass. The issue I'm running into is with frame edges - objects crossing the edge can lose their imagery. Normalizing the vector blur node in Nuke 'fixes' this, but wrecks the rest of the alpha edge. Anyone solve anything like this with Vray settings? Or is this a Nuke-only problem?

[hermit.crab]

Not sure if this is V-Ray related. Using 'Normalize' does indeed fix the issue. Using overscan, expanding the blur bbox, and using a clamped VRayVelocity do not seem to improve the result. Maybe you could mask the alpha after normalizing?

[chronopsis]

It does seem to be a Nuke issue. Nuke's "detect plate" setting on read nodes supposedly repeats edge pixels by default, but even changing the default detect setting to always repeat edge pixels changes nothing. Unfortunately masking the alpha in the vector blur node seems to make it worse. I can't tell if it's masking after or before normalizing. In the meantime I'll just have to render motion blur in Vray.