When a repository gateway has been configured for a repository, there is the possibility to acquire a lease for a specific subpath.
$ cvmfs_server transaction <repo_name>/some/subpath
The same subpath has to be given to the publication command, at the end of the transaction:
$ cvmfs_server publish <repo_name>/some/subpath
This is due to an implementation detail and should not be needed, considering that only a single lease can be acquired on each machine.
The solution of this issue involves renaming the file where the session token obtained from the gateway is stored.