It seems as if all of the values of the intended RGB tuple are shifted to the right one
The Arduino is programed in C and there is no such thing as a tuple in C. That is a data construct used in Python.
What you have here is a class method called 'Color' and you are passing to it three numbers.
As to why you are having problems is anyone's guess because you have not posted all your code like it says in the How to use this forum thread that you should have read.