Trouble with restart

I'm having issues with the restart and read_restart commands.

In my example simulation, I have a box filled with particles, which are then indented by a cylinder.

The simulation runs fine, and I have it output restart data at every 2000 timesteps.

When I attempt to restart from any of those files, the output from the new simulation shows ~1000 timesteps where the particles are spread through the domain, and fall to the bottom of the box:

Obviously this is not what I expect to happen, I expect the particles to be located at the bottom of the box, in the positions they were in at that point in the original simulation.

Any help would be much appreciated. Input files and image attached. I feel I'm missing something obvious, but I've spent a few days on this now with no luck.