[PyQt] Mouse pointer changing shape (blinking) on signals and QLineEdit text cursor blink

[David Morris]

I am developing a small media player application using PyQt5 on MacOS
Mojave. Any time the mouse is hovering over a widget where the mouse
pointer changes shape, the mouse pointer begins to blink (flash?), changing
shape between the normal mouse pointer and the alternate mouse pointer.

For example, if I create a QLineEdit widget the mouse pointer changes to an
I-Beam as the alternate pointer when hovering over the widget. Ordinarily
this the mouse pointer simply changes shape so long as I am hovering over
the widget. However, in the below test application the mouse pointer
continually changes shape between the I-Beam pointer and the normal arrow
mouse pointer, changing back and forth at the same rate as the input
position cursor in the widget.

Example code showing this behavior on my system:

import sysfrom PyQt5               import QtWidgetsfrom PyQt5
     import QtCore

class MainWindow(QtWidgets.QMainWindow):
    sig = QtCore.pyqtSignal()
    def __init__(self):
        super().__init__()
        self.resize(400,400)
        self.cw = QtWidgets.QWidget(self)
        self.setCentralWidget(self.cw)
        self.l = QtWidgets.QVBoxLayout(self.cw)
        self.le = QtWidgets.QLineEdit(self.cw)
        self.l.addWidget(self.le)
        self.label = QtWidgets.QLabel()
        self.l.addWidget(self.label)
        self.show()

app=QtWidgets.QApplication([sys.argv])
w=MainWindow()
app.setActiveWindow(w)
exit_code = app.exec_()

sys.exit(exit_code)

In the above code I can fix the problem by disabling the line edit cursor
flash using app.setCursorFlashTime(0). However, this does NOT fix the
problem in my application. In my application, signals in other widgets will
also cause the same mouse pointer shape changing (blinking) behavior.

Version details:
*MacOS* Mojave 10.14.1
*PyQt5* 5.12.2
*Python* 3.7.3

I have developed QtApplications in the past and never observed this
behavior and am at a loss as to why this is happening.

It occurred to me this could be a MacOS bug, but I am unable to update my
system at the moment (I am on a very poor internet connection and the
update is huge).

Does anyone have a solution for this highly irritating behavior?

EDIT: Change "mouse cursor" to "mouse pointer" for clarity.
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