Particles that use source movement will start shooting out violently while in the cascade preview window. You need to have the movement option checked under the view settings. If you also check the bounds viewer (by clicking the bounds button at the top of the screen) you see the bounding box adapting in extreme ways while the system is in motion. During these "adjustments" the system will shoot out particles at high velocity.
This doesn't happen in the scene though.
The particle system will start circling the view and at certain points the particles will shoot out violently.
The particles circle the preview window in a manner consistent with source movement.
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