KeyError: 29, when Internet connection was dropped

Versions

OS: Ubuntu 20.04.2 LTS
GTK+ Version: 3.24.20
PyGObject Version: 3.36.0
python-nbxmpp Version: 0.6.10
Gajim Version: 1.1.3

Traceback

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/gajim/gui_interface.py", line 2251, in process_connections
    app.idlequeue.process()
  File "/usr/lib/python3/dist-packages/nbxmpp/idlequeue.py", line 583, in process
    self._check_time_events()
  File "/usr/lib/python3/dist-packages/nbxmpp/idlequeue.py", line 339, in _check_time_events
    self.queue[fd].read_timeout()
KeyError: 29

Steps to reproduce the problem

I couldn't reproduce it — it happened once when my Internet connection was dropped.