Using Modeler 18.104.22.168, I created a Time Plot where the 'Plot' parameter was set to "Selected Time Series models". The output chart displays no ticks nor tick labels on the vertical axis. Thus, one can't determine anything about the vertical scale.
The "Selected Time Series Models" standardizes the values, I think that’s why they decided not to show the axes’ values (everything would be between 0 a 1) . You can include your real, forecast, lower and upper interval variables in the plot option “Selected series” to show the axes’ values.