For the record I'll just add that the main fix that actually fixes the reported issue is this:

    def _on_code_lenses_resolved_async(self, mode: str) -> None:
        if self._is_listener_alive():
            sublime.set_timeout(lambda: self._code_lenses.render(mode))

So basically checking if the view listener is still alive after long-running request, and not handling the response if it isn't.

This is a pretty generic problem that we might want to find a generic solution for.