Problem

Error occurs in Interchange *_te.log :
2025-09-12 06:25:06,220 - ERROR [MaverickSSHEventedThread-1-2343] (SshVirtualFileSystem) - No username found in normPath. normPath = /user02/to/.working

Resolution

Enable DEBUG in /Interchange/conf/log4j2.xml will provide more information :
<!-- SFTP server -->
<Logger name="com.cyclonecommerce.collaboration.transport.sftp.server" level="INFO" />
<Logger name="com.cyclonecommerce.collaboration.transport.ssh.server" level="DEBUG" />
<Logger name="com.cyclonecommerce.tradingengine.transport.ssh.server" level="DEBUG" />

This log suggests:
SSH SFTP_FILE_DOWNLOAD_INIT |{}CONNECTION = com.maverick.sshd.Connection@6f5ee6a4|{}OP_STARTED = Fri Oct 24 06:15:06 UTC 2025|{}MOUNT_MANAGER = com.maverick.sshd.vfs.VirtualMountManager@c91aac8|{}FILE_FACTORY = com.maverick.sshd.vfs.VirtualFileFactory@361bab38|{}OP_FINISHED = Fri Oct 24 06:15:06 UTC 2025|{}NFS = com.cyclonecommerce.tradingengine.transport.ssh.server.SshVirtualFileSystem@2ac5ef0b|{_}_FILE_NAME = /user02/to/.working

The sftp client is initiating a download for __FILE_NAME = /user02/to/.working where ".working" is considered a filename, and not a directory.

The partner for which this is happening is using a sftp client that considers wrongly ".working" a file and tries to download it.
B2Bi is signalling this as an issue through this log:
2025-10-24 06:15:06,205 - ERROR [MaverickSSHEventedThread-1-9902] (SshVirtualFileSystem) - No username found in normPath. normPath = /user02/to/.working

Also it warns here that the sftp client is trying to consume a protected directory:
2025-10-24 06:15:06,205 - DEBUG [MaverickSSHEventedThread-1-9902] (SshVirtualFileSystem) - Do not consume. Protected directory in path /user02/to/.working

B2Bi is reacting to an action from SFTP Client.