Soft Body Particle Generation Problem

[apapaxionga]

When I created a fully setup soft body, everything works well. If I change the mesh scale and particle setting, the simulation looks good but sometimes the skin mesh disappear (seems like crashed). The same thing also happened when I changed the mesh object. I did initialize  the particle generation everytime I changed something. However, it still happens. How to solve this problem ? For now, I have to delete the whole soft body object and remember all the parameters. Then create a new softbody using the parameters. Then it works.