Wa Ha

It's not a bug. It's because the polys have a Cd attribute of 0,0,0 (black). They're also imported as a bezier nurbs.

You need a color sop to change to white (normal Houdini poly colour) and a convert sop to change to polys. You can adjust the resolution on the convert sop or use a resample before the convert to adjust the res.

Try this script
https://github.com/Aeoll/HipCollector [github.com]

Forgot to add the test file. Includes a .hip and the MIDI file. Tempo in Ableton was 100bpm.