hydra is network logon cracker which support many different services. I just found out that sometimes it has problems when trying to crack the ftp password of the server which has a long multiline banner. Sometimes hydra tries to send username before banner finishes, then waits for response, but receives just another line of banner. In such situation hydra thinks that login try failed.
I've done quick patch which seems to solve this problem. The patch works for me, but I haven't tried it too much. Be careful.
You can download the patch or just patched version of hydra.