So my guess is that it's just related to the vector field used for the Radial Zoom mode? Maybe it lacks density? It would be great to have the option to add custom vector fields is possible ;)
This seems to be an artifact with trying to accumulate some very flowy vector-field values onto a raster pixel grid, causing it to "miss" some pixels while integrating streamlines. Basically, it will increment the current pixel into the next pixel by sampling the vector-field, but will "miss" the diagonal pixel that it may have touched along the way without knowing that it crossed two pixels rather than one. 🤔
This might take some time to figure out how to remedy without breaking previous projects(and hypothetically adding custom vector field support), but I'll try and look into it without changing the core algorithm too much.
For now, one way to remedy this is to put the PixSort on its own layer with "Interval Matte" view mode and use the "Median" filter with a 1px radius and enable the "Operate On Alpha Channel" option
