White Knockout text printed in box ground when Black separation removed in Acrobat

Question

I'm using tcolorbox to tackle a knockout text issue inside a colour box. When I deselect the black color in "Separation" option in the PDF Output Preview, a box backdrop with white text is printed.

MWE:

\documentclass{book}
\RequirePackage[many]{tcolorbox}
\definecolor{lightblue}{cmyk}{0.25,0.08,0.01,0.05}
\definecolor{darktabblue}{cmyk}{1.0,0.9,0.1,0.0}
\newtcolorbox{tablebox}[1]{%
%breakable,
arc=0pt,outer arc=0pt,boxrule=0.0pt,boxsep=0pt,top=0pt,left=6pt,right=6pt,bottom=6pt,middle=0pt,
toptitle=5.5pt,bottomtitle=14.4pt,
colback=lightblue!150, colbacktitle=darktabblue,%bottomrule=0pt,toprule=0pt,rightrule=0pt,leftrule=0pt,
colframe=black, coltitle=white,lefttitle=6pt,righttitle=6pt, titlerule=0pt,left skip=0pt,right skip=-13pt,%titlerule style={tenprcntblack,line width=0pt},
title=#1,
before app={\par\addvspace{0pt}\noindent},
after app={\par\addvspace{0pt}}
}%
\begin{document}
\begin{tablebox}{Title}{
  The distribution of data is really a theoretical concept
that is usually an assumption underlying any statistical test. In
informal terms, the distribution is the probability that particular
values of data are likely to turn up. To make this more concrete,
let's start with one of the simplest types of data, Likert item data,
where people respond with numbers between 1 (strongly disagree) and
5 (strongly agree).}
\end{tablebox}
\end{document}

Answer 1

With the pdfmanagement (that you load with \DocumentMetadata) you can do something like this:

\DocumentMetadata{}
\documentclass{book}
\ExplSyntaxOn
\pdfmanagement_add:nnn 
 { Page / Resources / ExtGState } 
 { text.overprinttrue } 
 { << /op~true /OP~true /OPM~1 >> }
\pdfmanagement_add:nnn 
 { Page / Resources / ExtGState } 
 { text.overprintfalse } 
 { << /op~false /OP~false  >> } 
\ExplSyntaxOff
\usepackage{iftex}
\ifpdftex
  \newcommand \enableoverprint {%
    \pdfliteral page {/text.overprinttrue gs}%
  }
  \newcommand \disableoverprint {%
    \pdfliteral page {/text.overprintfalse gs}%
  }
\else
  \RequireLuaTeX
  \newcommand \enableoverprint {%
    \pdfextension literal page {/text.overprinttrue gs}%
  }
  \newcommand \disableoverprint {%
    \pdfextension literal page {/text.overprintfalse gs}%
  }
\fi
\RequirePackage[many]{tcolorbox}
\selectcolormodel{cmyk}
\definecolor{lightblue}{cmyk}{0.25,0.08,0.01,0.05}
\definecolor{darktabblue}{cmyk}{1.0,0.9,0.1,0.0}
\newtcolorbox{tablebox}[1]{%
%breakable,
arc=0pt,outer arc=0pt,boxrule=0.0pt,boxsep=0pt,top=0pt,left=6pt,right=6pt,bottom=6pt,middle=0pt,
toptitle=5.5pt,bottomtitle=14.4pt,
colback=lightblue!150, colbacktitle=darktabblue,%bottomrule=0pt,toprule=0pt,rightrule=0pt,leftrule=0pt,
colframe=black, coltitle=white,lefttitle=6pt,righttitle=6pt, titlerule=0pt,left skip=0pt,right skip=-13pt,%titlerule style={tenprcntblack,line width=0pt},
title=#1,
before app={\par\addvspace{0pt}\noindent},
after app={\par\addvspace{0pt}}
}%
\begin{document}
\begin{tablebox}{Title}{
\enableoverprint
  The distribution of data is really a theoretical concept
that is usually an assumption underlying any statistical test. In
informal terms, the distribution is the probability that particular
values of data are likely to turn up. To make this more concrete,
let's start with one of the simplest types of data, Likert item data,
where people respond with numbers between 1 (strongly disagree) and
5 (strongly agree).}
\disableoverprint
\end{tablebox}
\begin{tablebox}{Title}{
  The distribution of data is really a theoretical concept
that is usually an assumption underlying any statistical test. In
informal terms, the distribution is the probability that particular
values of data are likely to turn up. To make this more concrete,
let's start with one of the simplest types of data, Likert item data,
where people respond with numbers between 1 (strongly disagree) and
5 (strongly agree).}
\end{tablebox}
\end{document}