圆角 mdframed 上的阴影模糊

Question

我得到了我的 mdframe 样式的这个定义：

\documentclass[final]{beamer}
\mode<presentation> {
\usetheme{CambridgeUS}
  }
\usepackage[utf8]{inputenc}
  \usepackage{amsmath,amsthm, amssymb, latexsym}
  \usepackage[orientation=portrait,size=a0,scale=1%,debug]
  ]{beamerposter}                       % e.g. for DIN-A0 poster
  \usepackage{textpos}
%For Tikz
\usepackage{tikz}
\usetikzlibrary{arrows,snakes,shapes}
\tikzset{>=latex}
\usetikzlibrary{backgrounds}
\usetikzlibrary{decorations.text}
\usetikzlibrary{decorations}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{decorations.pathreplacing}
\usetikzlibrary{calc}
\usetikzlibrary{%
    calc,%
    fadings,%
    shadings%
}
\usetikzlibrary{arrows,snakes,shapes}
\usetikzlibrary{backgrounds}
\usetikzlibrary{
    shapes.geometric,
    decorations.pathreplacing
}
\usetikzlibrary{patterns}
\def\zangle{-20}
\def\xangle{20}
\usepackage[font={Large},labelfont={Large,color=MyBlue}]{caption}
\usepackage{lipsum}
%**************************************************************
\usepackage{setspace}
\definecolor{MyGreen-gray}{gray}{0.5383}
\definecolor{MyBlue}{RGB}{29,47,160}
\setbeamercolor{frametitle}{bg=MyBlue,fg=white}
\setbeamercolor{block title}{bg=MyBlue,fg=white}

\usetikzlibrary{shadows}
\usetikzlibrary{shadings}
\usetikzlibrary{shadows.blur}

\usepackage[framemethod=TikZ]{mdframed}
\mdfdefinestyle{Blocco}{%
rightline=false,leftline=false,topline=false,bottomline=false, innerleftmargin=10,innerrightmargin=10,innertopmargin=10, innerbottommargin=10,linewidth=3.0pt, linecolor=black, roundcorner=4pt,frametitlefont=\Huge\textcolor{white} ,frametitlebelowskip=0.3cm,frametitleaboveskip=0.3cm, frametitlebackgroundcolor=MyBlue, backgroundcolor=MyBlue!7, shadow=true, shadowsize=5pt,middleextra={
\foreach \sshift/\svalue in {6/gray!10,5/gray!20,4/gray!30,3/gray!40,2/gray!50,1/gray!60}
  {
  \fill[\svalue] 
    (P) --
    ([xshift=\sshift pt]P) -- 
    ([xshift=\sshift pt]P|-O) --
    (P|-O) -- cycle;
  }
},
secondextra={
\foreach \sshift/\svalue in {6/gray!10,5/gray!20,4/gray!30,3/gray!40,2/gray!50,1/gray!60}
  {
  \fill[\svalue,rounded corners] 
    ([xshift=\sshift]O) --
    ([xshift=\sshift,yshift=-\sshift]O) --
    ([xshift=\sshift,yshift=-\sshift]P|-O)
    {[sharp corners] -- ([xshift=\sshift]P) -- 
    (P)} -- 
    (P|-O) -- ([xshift=\sshift]O);
  }
},
firstextra={
\foreach \sshift/\svalue in {6/gray!10,5/gray!20,4/gray!30,3/gray!40,2/gray!50,1/gray!60}
  {
  \fill[\svalue,rounded corners] 
    ([yshift=-\sshift]P) --
    ([xshift=\sshift,yshift=-\sshift]P) 
    {[sharp corners] -- ([xshift=\sshift]P|-O) -- 
    (P|-O)} -- ([yshift=-\sshift]P);
  }
},
singleextra={
\foreach \sshift/\svalue in {6/gray!10,5/gray!20,4/gray!30,3/gray!40,2/gray!50,1/gray!60}
  {
  \fill[\svalue,rounded corners] 
    ([xshift=\sshift]O) --
    ([xshift=\sshift,yshift=-\sshift]O) --
    ([xshift=\sshift,yshift=-\sshift]P|-O) --
    ([xshift=\sshift,yshift=-\sshift]P) -- +(-6pt,0) --
    (P) -- 
    (P|-O) -- ([xshift=\sshift]O);
  }
}}

\begin{document}
\begin{frame}{} 


%****************************************************************
%Titolo
\begin{textblock}{10.1}(2.6,-4)
{{\fontsize{120}{60}\selectfont S}}{{\fontsize{95}{60}\selectfont{\MakeUppercase{p }}}} {{\fontsize{120}{60}\selectfont A}}{{\fontsize{95}{60}\selectfont{\MakeUppercase{ct }}}}\\[1cm]
\begin{center}
{\huge{Quantum correlations}}
\end{center}
\end{textblock}     
    %****************************************************************

\begin{textblock}{10}(2.6,-2.5) 
\begin{mdframed}[style=Blocco,frametitle={Abstract}]
{\fontsize{44pt}{50pt}\selectfont
\lipsum[1]}
\end{mdframed}
\end{textblock}

\begin{textblock}{10}(2.6,4.5)  
\begin{block}{Abc}
\lipsum[1]
\end{block}
\end{textblock}
\end{frame}
\end{document}

我的问题是pdf结果的圆角有问题，如图所示。我的想法是mdframed框的阴影的圆角应该像经典的块一样。

如果有人能解决这个问题那就太好了！！