I have a library chart that I reuse multiple times in a model. The data type of the library chart input is set to 'Inherit: Same as Simulink'.
In addition, the incoming data type is different for each chart instance in the model, e.g. double and int8. When compiling the model the types displayed in the model are 'correct'. (see picture 1)
But now, chart input type is randomly chosen in the Model Explorer. (Picture 2 & 3)
Also, the type returned by the Simulink API is random but the same for both inputs of the chart instances. Is that a desired behaviour? It seems very weird to me.
For your reference I attached a minimal example model (2018b), also.