QCursor::pos() returns wrong results on a multi-monitor setup when HiDPI is enabled

Run the following script with environment QT_SCALE_FACTOR=2, then move the cursor around. The output value jumps whenever the cursor crosses the monitor boundary.

#!/usr/bin/python3
import sys
from PyQt5.QtWidgets import QApplication
from PyQt5.QtCore import QObject
from PyQt5.QtGui import QCursor
from PyQt5.QtCore import QTimer

a = QApplication(sys.argv)
t = QTimer()
t.setSingleShot(False)
t.setInterval(50)
t.timeout.connect(lambda: print(QCursor.pos().x(), QCursor.pos().y()))
t.start()
a.exec()

My test setup consists of a 2560x1440 display and a 1920x1080 display to its right. The X coordinate is in range of [0,1280] when the cursor is on the first display and [2560,3520] when it's on the second display, rendering the result from QCursor::pos() mostly unusable.