CPUParticles3D emitter continues to generate particles even when the `emitting` is set to `false`

[patwork]

Tested versions

4.4.1.stable (win & linux)

System information

Windows 10 / 11, Ubuntu 24.04

Issue description

When the CPUParticle3D emitter uses a mesh with a material that has the 'Billboard' option enabled but the 'Keep Scale' option disabled, particles continue to be generated and displayed for a while after the 'Emitting' option is toggled off.

Enabling "Keep Scale" fixes the issue. Perhaps this option should be enabled by default? #76328

This problem does not occur in GPUParticle3D.

movie.mp4

Steps to reproduce

1. create CPUParticle3D
2. add mesh
3. add material
4. enable billboard mode in material settings
5. start / stop emitter

Minimal reproduction project (MRP)

particles-compat.zip