No interpolated child hairs are created for parent/guide hair created in particle edit. Only parent/guide hair created with the Emission part of the particles panel can have interpolated children.
This is true for cycles, eevee, and all viewport displays. Hair particles created with Add and with Particle->Mirror have this problem.
Particle Edit view. The parent hair on the left is from the emission panel. The hair on the right is from Particle->Mirror.
I’m having the same exact problem after 2 years on blender 3.1.2
When I needed to add some hair particles to some spots, I have entered particle edit, added the hair particles, came back, nothing changed. Switching from Interpolated to None fixes the problem, but these particles just don’t show up in interpolated. I guess I have to redo a new particle system from scratch to add this, but I’m confused how is this happening.
On the top you can see newly added particles, but nothing shows up in interpolated.
