It does seem like there are some particles that aren’t going directly away from the center of the particle system, but seems like it’s like the tail end of the particle animation (it’s animating from red to green to blue), and they seem to be animating close to the edges of the extents.
Also, is it weird at all how the particles seem to be bouncing backwards near the square extents?
The top left example object has a sphere shaped particle emitter, while the bottom right one is a cube shaped particle emitter (they look pretty much the same to me).
This looks like a bug tbh.
Particle positions state is normalized to AABB of a particles, and it seems that AABB is a bit smaller than it supposed to be, leading to particles being wrapped around.