During an initial sync it is not possible to connect and therefore, collect any monitoring data as per authentication issues. Please note that the initial sync for big volumes of data can take many days.
However, at that code, the "fetching and creating collections" stage runs on a list where "admin" has been moved to the first element. But that database name gets inserted into a lexicographically sorted map, which is used to invoke the "initial sync cloning db" stage. "activities" sorts before "admin" so gets cloned first.