Cloning produces error "Cannot read property 'toResolveHierarchy' of undefined"

I’m trying to create multiple instances of i18next with different lng:

import i18next from 'i18next'

const auto = i18next.createInstance ({
	debug: !!FocusCraft.config.debug,
	load: 'languageOnly',
	lng: navigator.language || navigator.userLanguage,
	fallbackLng: 'en',
	resources: {
		en: {
			hello: 'Hello World!',
		},
		ru: {
			hello: 'Привет мир!',
		},
	},
})

const locales = {
	en: auto.cloneInstance ({ lng: 'en' }),
	ru: auto.cloneInstance ({ lng: 'ru' }),
}

…But once it gets to cloneInstance(), i18next dies with an error:

i18next.js:273 Uncaught TypeError: Cannot read property ‘toResolveHierarchy’ of undefined at setLng (i18next.js:273) at I18n.changeLanguage (i18next.js:290) at load (i18next.js:159) at I18n.init (i18next.js:169) at I18n.cloneInstance (i18next.js:392) at Object.defineProperty.value (i18n.js:19) at webpack_require (bootstrap 06f5bf9…:19) at Object.defineProperty.value (App.jsx:9) at webpack_require (bootstrap 06f5bf9…:19) at Object.defineProperty.value (AppContainer.jsx:5) at webpack_require (bootstrap 06f5bf9…:19) at Object.<anonymous> (main.jsx:11) at webpack_require (bootstrap 06f5bf9…:19) at Object.<anonymous> (emitter.js:2) at webpack_require (bootstrap 06f5bf9…:19) at bootstrap 06f5bf9…:65

In this case, I’d really like to keep several instances. I could just create them individually, but clones would be better, as they supposedly share resources. Am I using clones in a wrong way?