Initial particle jitter when using shader for ProcessMaterial

[Ewall198]

Tested versions

• Reproducible in: 4.4.stable, 4.3.stable, 4.2.stable, 4.1.stable

System information

Windows 10 - Godot 4.4.stable - Vulkan (Forward+) - Nvidia GeForce RTX 3060

Issue description

GPUParticles3D briefly shows particles in wrong position when creating one_shot explosion with particles.

Particle.Jitter.Example.mp4

Steps to reproduce

Create a GPUParticles3D node which has one_shot = true, explosiveness = 1, and a simple ShaderMaterial for process_material.
Set emitting = true after lifetime has expired.

The particles will briefly appear in their previous positions, before appearing in the correct positions.

Minimal reproduction project (MRP)

particle_jitter_bug.zip

[Ewall198]

Here's a slice of the example video slowed down 10x.

Particle.Jitter.Example.10x.mp4