Please make sure you have “undetermined” selected in your list of spoken languages in your lemmy settings in addition to any other languages you speak.
Most lemmy content does not come through with a language tag, and you need to have undermined selected as an option to see that content.
I have seen some other instances where the undetermined_language_warning field has some explanatory text. Maybe there is a variable somewhere that can be configured?
For example, on Beehaw:
It will be fixed when we update the version we’re running (which will be soon)