After new update the mesh will disappear in many cases ....

After 0.3 update the mesh will disappear in many cases, even with same code and same STL model the mesh is not generate and there is no object to simulate.
Here an example with previous build:

Same code, same STL, ... with latest build:

i test it with at least 10 different models, if there is an small issue in model it will not work anymore but in previous build it was much more stable and better. also the performance was a bit better with previous build as well (very small but better)