Some questions about the vashishta

Recently, I am running a simulation about the cracking of sic by lammps. And the potential I choose is SiC.vashishta(from lammps/SiC.vashishta at 2d4f030f113f179411bb3bc6afe97adec8bd62b5 · lammps/lammps · GitHub) according to some articles. However, the workpiece will disappear when the diamond tool get close to the workpiece. Is the phenomenon normal? What are the reasons for this phenomenon?

The most common reason for this kind of behavior is that the tool is moving too fast. A high-speed impact can easily pulverize an object.
Another, less likely explanation would be that the potential function or its parameters are not suitable. You could check if the same happens (or not) with switching to a Tersoff potential, for example.

Thanks a lot.