There are bugs for NSSpellChecker going back as far as 2009 regarding automatic language detection (they're, however, now annoying as piss to link to... because all the old mailing lists/archives have been seemingly nuked. Thanks, Cocoa community!). This in turn hits Electron apps, since they're just passing back to the native API anyway.
https://github.com/electron-userland/electron-spellchecker/i...