The line density tool has a default symbology so that the raster when added to ArcGIS Pro it shows purple. The problem is that it makes it appear that areas that have lines are showing up as white background. This immediately makes the user think that the algorithm is wrong. The symbology also persists. If I remove the layer and add it back it will render it the same. I would recommend Esri immediately abandon this default symbology and switch to something else. The default raster symbology is much better.