pyqt5 - error zsh: segmentation fault on Mac OS Monterey 12.4

Question

Running the python program whose code is shown below I got "error zsh: segmentation fault". The program simply displays a form containing an empty QTableWidget and when the QPushButton 'pbNuovoMargine' is clicked it inserts a new row in the QTableWidget; upon the input of each item in the QTableWidget it calls a function to align the fields entered using delegates. The problem is occurring when the function for fields alignment is called: what is happening is the first value entered at position 0,0 is aligned as expected while when starting entering the second value generates the error "error zsh: segmentation fault". It seems that the 'itemChanged' signal is emitted not only when the item is changed. Any help is appreciated

import sys
from PyQt5 import QtWidgets, QtCore, QtGui
from PyQt5.QtCore import QSize, Qt, QModelIndex
from PyQt5.QtWidgets import QApplication, QTableView,QWidget
from PyQt5.QtWidgets import  QPushButton, QItemDelegate, QStyledItemDelegate
from gestione_gross_marginUi import Ui_f_GrossMargin

class GrossMargin(QWidget, Ui_f_GrossMargin):
    def __init__(self):
        super().__init__()      
        
        self.setupUi(self)
        self.impostazione_data_mapper()
       
        self.tW_GrossMargin.itemChanged.connect(self.allinea_campi)
        self.pbNuovoMargine.clicked.connect(self.nuovo_margine)
    
    def impostazione_data_mapper(self):
        font = QtGui.QFont()
        font.setBold(True)
        self.tW_GrossMargin.setColumnCount(7)
        self.tW_GrossMargin.setRowCount(10)
        self.tW_GrossMargin.setSizeAdjustPolicy(QtWidgets.QAbstractScrollArea.AdjustToContents)
        
        intestazioni=[]
        intestazioni.append("Range - quantità da")
        intestazioni.append("Range - quantità a")
        intestazioni.append("Vendita - Gross margin Italia")
        intestazioni.append("Vendita - Gross margin Estero")
        intestazioni.append("Conto lavorazione - Gross margin Italia")
        intestazioni.append("Conto lavorazione - Gross margin Estero")
        intestazioni.append(" ")
        self.tW_GrossMargin.setHorizontalHeaderLabels(intestazioni)
        
        self.tW_GrossMargin.resizeColumnsToContents()
        header = self.tW_GrossMargin.horizontalHeader()
        header.setDefaultAlignment(Qt.AlignCenter|Qt.AlignVCenter)
        self.tW_GrossMargin.resizeColumnsToContents()

        for c in range(self.tW_GrossMargin.columnCount() - 1):
         h_item = self.tW_GrossMargin.horizontalHeaderItem(c)
         h_item.setFont(font)

        self.tW_GrossMargin.resizeColumnsToContents() 


    def allinea_campi(self):
      r=self.tW_GrossMargin.currentRow()
      c=self.tW_GrossMargin.currentColumn()
      if c==0 or c==1:
         self.tW_GrossMargin.setItemDelegateForColumn(c, IntDelegate(self.tW_GrossMargin))
      else:
         self.tW_GrossMargin.setItemDelegate(FloatDelegate(3, self.tW_GrossMargin))
 
    def nuovo_margine(self):  
  
      numRows = self.tW_GrossMargin.rowCount()
      self.tW_GrossMargin.insertRow(numRows)    
         
class IntDelegate(QStyledItemDelegate):
    def __init__(self, parent=None):
      super().__init__()
   
    def paint(self, painter, option, index):    
        value = index.model().data(index, Qt.EditRole) 
        print(value)
        number=str(value)    
        painter.drawText(option.rect, Qt.AlignCenter, number)
              
class FloatDelegate(QItemDelegate):
    def __init__(self, decimals, parent=None):
        QItemDelegate.__init__(self, parent=parent)
        self.nDecimals = decimals

    def paint(self, painter, option, index):
          value = index.model().data(index, Qt.EditRole)
          try:
             number = float(value)
             painter.drawText(option.rect, int(Qt.AlignCenter | Qt.AlignVCenter), "{:.{}f}".format(number, self.nDecimals))
          except :
             QItemDelegate.paint(self, painter, option, index)

app = QApplication(sys.argv)
window = GrossMargin()
window.show()
sys.exit(app.exec_())

-- .ui file --

from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_f_GrossMargin(object):
    def setupUi(self, f_GrossMargin):
        f_GrossMargin.setObjectName("f_GrossMargin")
        f_GrossMargin.resize(636, 315)
        self.gridLayout = QtWidgets.QGridLayout(f_GrossMargin)
        self.gridLayout.setObjectName("gridLayout")
        self.verticalLayout = QtWidgets.QVBoxLayout()
        self.verticalLayout.setObjectName("verticalLayout")
        self.tW_GrossMargin = QtWidgets.QTableWidget(f_GrossMargin)
        self.tW_GrossMargin.setStyleSheet("background-color: rgb(255, 251, 0);\n"
"border-color: rgb(255, 38, 0);\n"
"")
        self.tW_GrossMargin.setObjectName("tW_GrossMargin")
        self.tW_GrossMargin.setColumnCount(0)
        self.tW_GrossMargin.setRowCount(0)
        
        self.verticalLayout.addWidget(self.tW_GrossMargin)
        self.gridLayout.addLayout(self.verticalLayout, 0, 0, 1, 1)
        self.horizontalLayout = QtWidgets.QHBoxLayout()
        self.horizontalLayout.setObjectName("horizontalLayout")
        self.pbNuovoMargine = QtWidgets.QPushButton(f_GrossMargin)
        self.pbNuovoMargine.setObjectName("pbNuovoMargine")
        self.horizontalLayout.addWidget(self.pbNuovoMargine)
        self.pushButton_2 = QtWidgets.QPushButton(f_GrossMargin)
        self.pushButton_2.setObjectName("pushButton_2")
        self.horizontalLayout.addWidget(self.pushButton_2)
        self.pushButton_3 = QtWidgets.QPushButton(f_GrossMargin)
        self.pushButton_3.setObjectName("pushButton_3")
        self.horizontalLayout.addWidget(self.pushButton_3)
        self.gridLayout.addLayout(self.horizontalLayout, 1, 0, 1, 1)

        self.retranslateUi(f_GrossMargin)
        QtCore.QMetaObject.connectSlotsByName(f_GrossMargin)

    def retranslateUi(self, f_GrossMargin):
        _translate = QtCore.QCoreApplication.translate
        f_GrossMargin.setWindowTitle(_translate("f_GrossMargin", "Impostazione Gross Margin"))
        self.pbNuovoMargine.setText(_translate("f_GrossMargin", "Nuovo margine"))
        self.pushButton_2.setText(_translate("f_GrossMargin", "PushButton"))
        self.pushButton_3.setText(_translate("f_GrossMargin", "PushButton"))