Following are a number of back-translations as well as a sample translation for translators of Jeremiah 10:21:

• Kupsabiny: “What caused these matters to come is that
  the shepherds are foolish so they did not ask God for advice.
  Therefore, that is what made them not to prosper,
  and all their sheep were scattered.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “This happened to us (incl.) for our (plur.) leaders/[lit. heads] are senseless/crooked; they do- not -take-refuge to the LORD. So they do- not -prosper, and all their men were-scattered.” (Source: Hiligaynon Back Translation)