Comment 14 for bug 1713391

Are you sure that sogoupinyin is causing your problem?

Invalid gsettings key in override file should not be problem. Override file is only used to compile gschemas.compiled file and invalid / unknown keys are simply ignored. Unless fcitx is hard requirement for something I doubt that your problem is related to GSettings.

In any case someone should fix that override file by removing invalid key or replace it with correct key - overrides.

Untested, but correct override might look like this:
overrides={'Gtk/IMModule': <'fcitx'>}