Matlab pool in simulink optimization

Hello, I'm doing an optimization work at Simulink using the response optimization gui. When i run this optimization everything is ok at the model starts updating the work variables according to the cost function I defined. But then I want to increase the speed of optimization so I have to use matlabpool and I can connect 4 workers. The problem is that when I use this 4 workers to do the optimization, it does not update the work variables and the optimization does not decrease the value of the cost function and stops after 10 iterations with the same value as when it first started. Do anybody knows why this is happening?

Thank you in advance ;)