Since the last upgrade, if you use the "snippets" plugin,

1) when a document is loaded, although nothing anomalous seems to happen, you
will see in the terminal

(gedit:12519): GLib-GObject-CRITICAL **: g_value_unset: assertion `G_IS_VALUE
(value)' failed
Traceback (most recent call last):
  File "/usr/lib/x86_64-linux-
gnu/gedit/plugins/externaltools/windowactivatable.py", line 217, in
do_update_state
    self.menu.filter(self.window.get_active_document())
  File "/usr/lib/python3/dist-packages/gi/_gobject/propertyhelper.py", line
215, in __get__
    value = instance.get_property(self.name)
TypeError: unknown type (null)
Traceback (most recent call last):
  File "/usr/lib/gedit/plugins/latex/windowactivatable.py", line 385, in adjust
    for name in self._action_objects:
TypeError: Couldn't find conversion for foreign struct 'cairo.Context'
Traceback (most recent call last):
  File "/usr/lib/gedit/plugins/latex/windowactivatable.py", line 385, in adjust
    for name in self._action_objects:
TypeError: Couldn't find conversion for foreign struct 'cairo.Context'

2) if you try to open the "Manage snippets" dialog, it won't open, and instead
you see in the terminal

(gedit:12421): GLib-GObject-CRITICAL **: g_value_unset: assertion `G_IS_VALUE
(value)' failed
Traceback (most recent call last):
  File "/usr/lib/x86_64-linux-gnu/gedit/plugins/snippets/windowactivatable.py",
line 209, in on_action_snippets_activate
    self.create_configure_dialog()
  File "/usr/lib/x86_64-linux-gnu/gedit/plugins/snippets/windowactivatable.py",
line 206, in create_configure_dialog
    SharedData().show_manager(self.window, self.plugin_info.get_data_dir())
  File "/usr/lib/python3/dist-packages/gi/_gobject/propertyhelper.py", line
215, in __get__
    value = instance.get_property(self.name)
TypeError: unknown type (null)