Ryugu showed an estimated ~20,000 different organic molecules. It's not that surprising that the nucleobases would be among them, along with all sorts of chemicals not relevant to life.
In the reference from the link for this HN entry, we see the nucleobases were present at concentrations of about 1 nano-mole per gram (< 1 ppm). They are minor constituents present in a sea of mostly non-biologically relevant compounds.
https://www.science.org/doi/10.1126/science.abn9033
In the reference from the link for this HN entry, we see the nucleobases were present at concentrations of about 1 nano-mole per gram (< 1 ppm). They are minor constituents present in a sea of mostly non-biologically relevant compounds.