Motion blur on Tracers with Spline warp gives jagged line problems

[context-leave]

I have attached a textured high-polycount plane with Spline wrap to a tracer line attached to animated geo here. Its following the animated geo in a rather rapid manner here.

Problem is it looks fine in the IPR, it even looks fine for a few frames in the render (I'm using Redshift) but everything is starting to look very jagged the more frames you render. The smooth flowy textured lines are being destroyed when motion blur is enabled it seems.

This is how it looks without motion blur (different frame)

From the look of things here its like its confused knowing where the velocity is taking place?

Things I have tried:

• Exporting the line in alembic
  ( not an option for this setup it would take way too long for all the tracers I have setup and it seems to break when trying to bake in the animated displacer I have also attached to it)
• Changed the interpolation of the spline to different methods and increase the number of points, didn't help at all.
• Changed the sample step in the tracer line to much lower value of 1
• Increase Simulation substeps in project settings from 20 to 60, iterations from 1 to 2. (no change I guess it doesn't affect it as its not a real sim)
• Turn motion blur off and export a Motion Vector pass Aov, but this seems to enable the same problem just indirectly.

It seems like I'm out of options here, and I really need to render this with Motion blur. They look fine without Motion blur enabled but it would be too tricky in comp since they cross-over a lot.

Anybody have a clues?

Thank you for your time!