One of the reason this happens is when a behavior has a dynamic view element in the Input or output variable ex:syzDisplayDetail and then the user turns the that view element "is dynamic" property to No "No" without removing the view element variable. variable in the start shape. To resolve this one can open make sure the respective .pmx file and remove the variables. "is dynamic property" is set to "Yes". It is always best to avoid this situation by carefully removing the variable before changing the view element property.