Why is this cylinder lunging?

An automotive assembly plant installed a simple two speed circuit to advance a hydraulic cylinder
at high speed and then switch to slow speed for pressing, as shown below.

Shifting of the two position solenoid valve (item 2) is causing a jolt which allows
unwanted movement of the stamping.

Do you know what is causing the jolt when the cylinder changes speed and how to eliminate it?

To understand this problem - and its solution, watch this simulation video.
(click on the arrow button (>) in the bottom left hand corner to start the video)

And to find out how you can get started in hydraulic simulation, click here

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CLICK HERE to find out how to get started in hydraulic simulation