Weird braces tikz/decoration

Question

The right end of the braces is compiling weird in every program that I tried to use. Can someone help me, please?

\documentclass[tikz,border=5]{standalone}
\usepackage{tikz}
\usepackage[brazilian]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usetikzlibrary{decorations.pathreplacing}

\def\layersep{2cm}

\begin{document}
\begin{tikzpicture}[shorten >=1pt,->,draw=black!50, node distance=\layersep]
\tikzstyle{every pin edge}=[<-,shorten <=1pt]
\tikzstyle{neuron}=[circle,thin,draw=black!80,minimum size=20pt,inner sep=0pt]
\tikzstyle{annot} = [text width=2cm, text centered]
\tikzstyle{input}=[circle,,fill=none,minimum size=20pt,inner sep=0pt]

% Draw the input layer nodes
\foreach \name / \y in {1,...,4}
% This is the same as writing \foreach \name / \y in {1/1,2/2,3/3,4/4}
    \node[neuron] (I-\name) at (0,-\y) {$x_{\name}$};

% Draw the hidden layer nodes
\foreach \name / \y in {1,...,5}
    \path[yshift=0.5cm]
        node[neuron] (H1-\name) at (\layersep,-\y cm) {};


    % Draw the hidden layer nodes
\foreach \name / \y in {1,...,2}
    \path[yshift=0.5cm]
        node[neuron] (H2-\name) at (2*\layersep,-\y cm - 1.5 cm) {};

% Draw the second hidden layer nodes
\foreach \name / \y in {1,...,6}
    \path[yshift=0.5cm]
        node[neuron] (H3-\name) at (3*\layersep,-\y cm + 0.5 cm){};

% Draw the output layer node
\foreach \name / \y in {1,...,3}
    \path[yshift=0.5cm]
        node[neuron] (O-\name) at (4*\layersep,-\y cm - 1cm){};

    \foreach \name / \y in {1,...,3}
        \path[yshift=0.5cm]
    node[input] (Oy-\name) at (4.5*\layersep, -\y cm - 1cm) {$y_{\y}$};

% Connect every node in the input layer with every node in the
% hidden layer.
\foreach \source in {1,...,4}
    \foreach \dest in {1,...,5}
        \path (I-\source) edge (H1-\dest);

\foreach \source in {1,...,5}
    \foreach \dest in {1,...,2}
        \path (H1-\source) edge (H2-\dest);

\foreach \source in {1,...,2}
    \foreach \dest in {1,...,6}
        \path (H2-\source) edge (H3-\dest);

    \foreach \source in {1,...,6}
    \foreach \dest in {1,...,3}
        \path (H3-\source) edge (O-\dest);

    \foreach \source in {1,...,3}
            \path (O-\source) edge (Oy-\source);

    \draw[decoration=brace, decorate] (H1-1.north west |- 0,0.5) -- (H3-1.north east |- 0,0.5)
                            node (hiddenlayer) [midway, above=1pt] {\footnotesize{Hidden Layers}};


\end{tikzpicture}

\end{document}

Answer 1

Since you are using -> in all lines, in here

\begin{tikzpicture}[shorten >=1pt,->,draw=black!50, node distance=\layersep]

You need to add - in this line so that -> in the default line is not used, therefore, the correct line is

\draw[decoration=brace, decorate,-] ...