Found another issue/question with what I was trying to do with a custom handler.

If one document has two identifiers that use different handlers; only the first one's env is updated. My templates error out because the default mkdocstring filters are missing (highlight, heading or convert_markdown) don't exist in the second handler yet and instead I only have the built-in jinja filters and the any filter that is added when the env is initialized.

::: mkdocstrings_handlers.custom_handler.other_module.AccessTypes
    handler: python

::: demo.custom_identifier.stuff
    handler: custom_handler

It looks like these few lines are the offenders and I'm curious if there is a drawback to updating it every time, updating the env on init or make the _updated_env a part of the handler and not the extension? Commenting out self._updated_env = True is enough to resolve this issue.

        if not self._updated_env:
            log.debug("Updating renderer's env")
            handler._update_env(self.md, self._config)  # noqa: WPS437 (protected member OK)
            self._updated_env = True