Black box over bracket when using \overbrace

Question

I'm using \overbace for some math formulas. At the begining everything works properly, but now when I compile file with an \overbrace I have some problem with the display of brackets.

For example, this line of code

$A'' = \langle Q', \Sigma, \delta', q_I', \overbrace{Q' \setminus F'}^{(F')^C}\rangle$

produces the following PDF:

Why does it display that awful black box over the bracket? I'm using TeX Live 2020

EDIT: This is the file:

\documentclass[a4paper, 11pt]{book}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english, italian]{babel}
\usepackage{subfiles}
\usepackage{braket}
\usepackage{amsfonts}
\usepackage{amsthm}
\usepackage{amsmath}
\usepackage{fdsymbol}
\usepackage{stmaryrd}
\usepackage{tabularx}
\usepackage{latexsym}
\usepackage{tikz}
\usepackage{thmtools}
\usepackage{mathtools}
\usepackage{hyperref}
\usepackage{graphicx}
\begin{document}
    Se $A'$  è un DFA allora avremo che 
    $A'' = \langle Q', \Sigma, \delta', q_I', \overbrace{Q' \setminus F'}^{(F')^C}\rangle$.
    Si ha che $A''$ è un DFA e si ha che $sc(L'') = sc(L')$.
\end{document}

Answer 1

First a caveat. Using fdsymbol changes all math symbols, using shapes that are not really compatible with Computer Modern. They're thought to accompany the Fedra typeface.

Your problem arises because fdsymbol redefines \underbrace and \overbrace, but mathtools changes them again using some assumptions that don't hold when the symbol font is provided by fdsymbol.

So load fdsymbol after mathtools (assuming you want to load it to begin with).