One has a typo, one doesn't "The light source emits light at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm." vs "The light source emit

One has a typo, one doesn't "The light source emits light at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm." vs "The light source emits light at at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm." ¯\_(ツ)_/¯