How to plot discrete variables in a linear model interaction using 'fitlm' and 'plotInteraction'?

Hi, I have a problem plotting the interaction of two variables in a linear model.

One of the variables (Diagnosis) has only 2 unique integer values, e.g. [0,1]. The other variable (Age) has many different values.

I created a model for a third variable, ImagVar, using the 'fitlm' function:

            DT=dataset(Age,Diagnosis,ImagVar,'Varnames',VarNames);
            mdl = fitlm(DT,'interactions','RobustOpts','on');

Then I plot them as:

            plotInteraction(mdl,'Diagnosis','Age','predictions');

The problem is that the resulting plot yields three lines: a red one for the '0' value of diagnosis, a purple one for the '1' value, and a yellow one for a value '0.5'.

I do not have any '0.5' value in my 'Diagnosis' variable, is there any way to plot only two lines (the red and the purple)?

Also, when I do the same but with 'Diagnosis' containing 3 non-sequental unique integer values, e.g. [0 1 4], the resulting plot yields a red line for the '0' value, a purple line for the '4' value and a yellow line for a value of '2', instead of the wanted value of '1'.

Thanks in advance!