Code generation error for Matlab System, Simulink

When I set the value of a property by matlab.system.stringset() method , everything works just fine (C/C++ code generates for arduino hardware successfully) . As per the newest documentation, mustBeMember(value, S) is prefered over the former one . But, when I do this, an error pops up during code generation phase . It says that error evaluating the value of propertyName .