Non escaped underscore in constrained quotes

[gionatamassibenincasa]

I expect that the snippet

The function ``sum_of_square``

The function **sum_of_square**

The function __sum_of_square__

This is a quote which uses a MACRO_NAME to trigger a bug 

would produce

The function \texttt{sum\_of\_square}

The function \textbf{sum\_of\_square}

The function \emph{sum\_of\_square}

This is a quote which uses a MACRO\_NAME to trigger a bug 

but I get

The function \texttt{sum_of_square}

The function \textbf{sum_of_square}

The function \emph{sum_of_square}

This is a quote which uses a MACRO_NAME to trigger a bug 

that is wrong.