AllNodesFailedException stores a map of errors internally, but that map is not printed to the logs by default.
If client code does not have access to that map (for example, because the error happened in production), the node errors are lost.
It would be nice to store each node error as a suppressed exception to AllNodesFailedException. This would allow consumers such as log libraries to display the suppressed exceptions if they want to. It would also allow to display all node errors, if the same node failed more than once (see JAVA-2527).