Why does the error "Cell contents reference from a non-cell array object" occure after 4 iterations while using parameter estimation.

The said error occures while using parameter estimation in simulink design optimization. The Parameters, I want to estimate are four 11x1 doubles. I attached a screenshot of the issue. I am trying to tune the parameters, to make my battery model's performance fit the drivecycle Voltage of an electric vehicle.

Furthermore, when I am in the dialog window to edit the estimated Parameters and I click on the yellow button to edit the parameters in the excel-like editor, I sometimes get a couple of errors popping up. I attached a picture of that. Strange thing is, that it doesnt occure every time. But often enough, to make it very annoying.

I am using matlab 2016b.