Blender

You know, I just read the title, saw the picture, and thought you modeled your own head to show the bald spots you were suffering from.

I'm thinking of creating a community called Mysteries of the 3D Realm, for inexplicable issues I seem to have on the reg. This will be post #1.

It’s hard to say for sure, I’m not very practiced on hair in Blender. But it looks quite similar to issues I’ve seen with baking normal maps where the low res mesh clips through the high res one, causing little diamond spots like these bald spots. Could it be that the target mesh is on the wrong side and therefore not finding the target location to plant a hair follicle in?

Again, I don’t use Blender hair in my line of work so I may be way off.

my weight maps and edit mode, no blue spots or funky geometry, no double verts...

Hey I asked you to be more flattering when you draw me! /j

I've only got basic experience with Blender's grooming system, but here are my would -be checkpoints:

1. Check the UV map is in good condition, that those bald polygons are properly mapped;

2. Check normals are facing the right way for the entire surface

3. Check the hair isn't poking through the other side or lying parallel to the surface, which seems obvious and you probably already did;

4. Check you are displaying all hair curves on your viewport, that your limits are enough for the amount of curves

I'm interested in the reason for this, now, too, just because I noticed it with the hair in KCD2 on some characters. Whatever it is, OP, even big pros have it.