Don't worry, The RAM is running at 2.1V if the BIOS says it is. If you really want to be safe, you you check the voltages the PSU is putting out along the 12V/5V etc rail(s) PC wizard can mesure this.
There's a new version on the Asus site, might be worth a try to see if the error is gone, I've linked to your boards d/load page, AI suite is under Utilities.