I doubt that. It is more likely that it is not considered a significant risk compared to everything else. How exactly is this information useful to adversaries? It certainly won’t help uncovering illegals, because their passports are kept away from Western databases. It doesn’t help to block spy operations, because you can connect passport numbers to specific actions only after they happened or you used other methods to detect spies. It doesn’t help breaking plausible deniability to blame Russian government officially, because you would need the hard evidence. So what’s the point in protecting this information more?