左下角出现虚假点，与森林相伴

Question

我在画树时遇到了一个非常奇怪的问题forest。在每棵树的左下角，我都会看到这个虚假的、错误的点。

以下是一个例子：

\usepackage{pgfplots} 
\pgfplotsset{width=12cm,compat=1.10} 
\pgfmathdeclarefunction{gauss}{2}{%   
\pgfmathparse{1/(#2*sqrt(2*pi))*exp(-((x-#1)^2)/(2*#2^2))}
} 
\usetikzlibrary{patterns}
\usepackage{adjustbox}
\usepgfplotslibrary{fillbetween}
\usepackage{forest}
\usepackage{listings}
\usepackage{amssymb}
%\usepackage[utf8]{inputenc}
\usepackage{xcolor}



\tikzset{     
    decision/.style={rectangle, minimum height=10pt, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    chance/.style={circle, minimum width=10pt, draw=black, fill=black!30!white, thick, inner sep=0pt},
    leaf-chance/.style={isosceles triangle, minimum width=10pt, draw=black, thick, fill=white, inner sep=0pt, 
shape border rotate=180, outer sep=-\pgflinewidth}   
}

\forestset{
 declare toks={optimality}{},
 declare toks={edge label below}{},
}

\begin{document}
\begin{center}


\begin{frame}

\scalebox{0.85}{
 \begin{forest}    
    my label/.style={       
        edge label={node[auto, sloped,pos=.75,anchor=south]{#1}}
    },
    my below/.style={
        edge label below={node[midway,below, pos = 0.75, font = \scriptsize,align = center]{#1}}
        %edge label={node[auto, sloped,pos=1.75,anchor=south]{#1}}
    },
    for tree={
      grow=0,
      child anchor=west,
      anchor=west,
      text ragged,
      inner sep=1mm,
      edge={thick, draw=black},
      l sep+=30mm,
      s sep+=5mm,
      if n children=0{
        before typesetting nodes={
          label/.wrap pgfmath arg={right:#1}{content()},
          content={},
          leaf-chance,
        },
      }{},
      edge path={
       \noexpand\path [draw, \forestoption{edge}] (!u.parent anchor) |- (.child anchor)\forestoption{edge label below}\forestoption{edge label};
  },
    }
    [, decision, label = left: HIV in Liberia,
        [,chance,my label=Treat all, label = right: 25.1
            [25, my label = HIV$^-$, my below = 0.985, tier = word]
            [30, my label = HIV$^+$, my below = 0.015, tier = word]
        ]
        [,chance,my label=Test all, label = right: 34.8
            [,chance, my label = HIV$^-$, my below = 0.985, label = above right: 34.9
                [35, my label= Test$^-\rightarrow$ Don't treat, my below = 0.99, tier = word]
                [25, my label = Test$^+\rightarrow$ Treat, my below = 0.01, tier = word] 
            ]
            [,chance, my label = HIV$^+$, my below = 0.015, label = above right: 28.6
                [2,  my label= Test$^-\rightarrow$ Don't treat, my below = 0.05, tier = word]
                [30, my label = Test$^+\rightarrow$ Treat, my below = 0.95, tier = word] 
            ]
        ]
    ]
\end{forest} }
\end{frame}

\end{center} 
\end{document}

生成以下树：

看到西南角的那个点了吗？我的文档中每棵树上都有这个点。我不知道如何去掉它。

谢谢你！