Sending any email fails after "BURL" command is sent

Sending email fails with QMF. I believe it is because of the BURL command sent, but I am not sure. This was experienced on an N9, running firmware 10.2011.34-1.339.01.2_PR_339, which carries libqmf0 version 2011W26-0maemo1-6+0m6.

The SMTP conversation goes (> sent, < received):

< 220 xxxx.example.com ESMTP Postfix
> EHLO [127.0.0.1]
< 250-gondolin.macieira.info
< 250-PIPELINING
< 250-SIZE
< 250-VRFY
< 250-ETRN
< 250-STARTTLS
< 250-AUTH LOGIN PLAIN DIGEST-MD5 CRAM-MD5
< 250-ENHANCEDSTATUSCODES
< 250-8BITMIME
< 250 DSN
> AUTH PLAIN
< 334
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
< 235 2.7.0 Authentication successful
> MAIL FROM: <thiago@example.com>
> RCPT TO: <thiago@example.com>
> BURL  LAST
< 250 2.1.0 Ok
< 250 2.1.5 Ok
< 502 5.5.2 Error: command not recognized

After the above, the connection is closed by the SMTP client (the QMF application).

Now, reading the QMF source code, it looks like it attempts to determine whether the server supports the BURL capability, which as shown above, this server does not. Yet QMF still tries to use the command.

The issue does not seem to be related to the use of pipelining. Trying on the same server after disabling pipelining results in:

> MAIL FROM: <thiago@example.com>
< 250 2.1.0 Ok
> RCPT TO: <thiago@example.com>
< 250 2.1.5 Ok
> BURL  LAST
< 502 5.5.2 Error: command not recognized