this is how it was supposed to sound:
https://drive.google.com/file/d/1Nz42N72xxsgUIKLeSpWuTvT8v1WbUnQm/view

it turns out the fix for the window function (in sunvox) was to write a set phase 0 pattern effect for the amp LFO at or before the beginning of the relevant pattern. i figured the phase would be reset automatically on export / playback from start but i guess not

https://drive.google.com/file/d/1ivDfFL9r3z4xjzRDAx3nNUJVAHU2hH8n/view
module for reference