Its not at all uncommon for it to admit ignorance, though it is less entertaining (and less likely to get posted publicly) than when it hallucinates something.
It's very inconsistent at admitting ignorance, though.
How many galaxies are in the Virgo Cluster?
> The Virgo Cluster is a cluster of galaxies that contains hundreds of individual galaxies. It is one of the largest galaxy clusters in the local universe, and it is located in the constellation of Virgo. The exact number of galaxies in the Virgo Cluster is not known, as it is constantly changing due to the motion of the galaxies within the cluster. However, it is estimated that the cluster contains at least 1,300 galaxies.
How many galaxies are in the Virgo Supercluster?
> It is estimated that the Virgo Supercluster contains approximately 100,000 galaxies.
When I ran the second query an hour ago, it replied that it didn't have access to the internet to look up the information.