How can you tell your immediate supervisor / BOSS that he's way beyond the limit of his actions without offending him/her?

I can tell him or her in light terms as a suggestion of how i think alternative way can be used. 

Start by a respect of he's position, by a good attitude share with him the issue.

You should talk to them and a nice way and to explain very well without offended like a family Be professional to treat your boss to respect each other.

By giving him respect and listening to what his saying without any bad response and attitude

By simply considering, he and his previous did wad astonishing but the current action is also effective, but if you don't mind I have one more suggestion if you like it.

Directly saying any thing could effect his ego.

Actually you should try to maintain your work ethics and always observe some professionalism

I request for appointment with him so that we discuss the unsuitable matters and come out with great solutions.

This calls for understanding and respect between the Employee and the employer. It has to be easy for me as an employee to confront my employer where I deemed important. If my employer gives jobs out of my work scope, I should seat him down with the copy of my contract and make him aware of the fact that , the tasks assigned are contrary to the initial agreement and try to understand why this is happening and the way forward

Depend on the type of override and there are transgressions that need direct and indirect clarification>

In my openion for every thing there is a right time to speak or to do in practical. So its important to do as the situation is and to follow.

I will accomplish the task/assigment then request for the best time with him so that he can clarify to me my job description and assignments in the company. The important thing is to have mutual understing with each other and in a respectful way.