In the latest version of Malstroem from Oct. 22 2024, all streamlines saved in the main.streams layer are cut off where they enter a bluespot at its max. extent. Instead, for partially filled bluespots it is proposed that the streamlines into a bluespot are cut off at the extent of the partially filled bluespot.
Next, it's up for discussion if a streamline carrying no spill over from a partially fileld bluespot should be visible at all. However, I recommend that such streamlines are preserved to inspect the overall connections inbetween bluespots. A streamline not carrying any spillover may just be excluded visually in a symbology step.
Kind regards, Thomas Balstroem