Why does St. Thomas Aquinas cite Proverbs 11:14 as Ecclesiastes 4:9?

I’m currently doing a read through of “On Kingship” (De Regno) by St. Thomas Aquinas. In paragraph 8, he cites Ecclesiastes 4:9 as saying >With this in mind, Solomon says [Eccl. 4:9]: “Where there is no governor, the people shall fall.” I went to lookup this verse in my Bible but it wasn’t there. On closer inspection, the best candidate I could find is Proverbs 11:14, which states: >Where there is no guidance, a people falls, but in an abundance of counselors there is safety. (ESV) Oddly, the only translation I can find that says “governors” is the Douay-Rheims translation. So given this, why does St. Thomas cite Ecclesiastes 4:9 when he’s obviously referring to Proverbs 11:14, and does the latin vulgate play a part in this as that’s where the D-R draws from?