When you enter a MBS function in a calculation on macOS, we show MBS in blue. The function name entered behind it as parameter turns blue if the function is known to the plugin. It will show in red while the function name is not correct. When you type something and you see it in red, then check for typos.
As you see we check both parts of the function independently. If the whole name is mistyped, it is all red. If one part is right, we show that part as blue. It can happen that you get two parts correct, but not the whole function and then the quotes and dot are red only.
This feature is always on if you have calculation coloring turned on via preferences dialog or the SyntaxColoring.Enable function.