Windows 7 + Linux
Broken: 2.69 + 2.70
Short description of error
Particles only collides correctly 1. time, next loop has weird wavy "collision" (attached blend + video)
Exact steps for others to reproduce the error
Setup basic particle emitter and collision plane, adjust so particles bounce off a little of the plane. Play animation and see correct/expected result. When the animation restarts the particle collision is wrong, and will stay that way until a setting (either particle or collision) is changed, then the collision is correct again, but only on the first play through. Baking particles does not work as it is not the expected result.