Bug in IMAP server protocol?

Hi, I am using Thunderbird as a client to connect to Zoho using IMAP. I have a problem where certain messages will not display properly in Thunderbird. Instead of seeing the message you just see a blank pane. But you can see the messages correctly on the Zoho website. The messages that won't display always contain an attachment.

I have done a lot of testing and I think I have found a problem with the IMAP software on the Zoho server.

Thunderbird sends the following IMAP command.
. uid fetch 14 (bodystructure)

The IMAP server at Zoho responds with the details of the body structure. But there is a syntax error in the message. One of the strings in the message, the Content-ID, does not have quotes around it. Please see the attached file LOG4.TXT for details. Thunderbird cannot understand this response and sends the logout command. The message is not displayed.

Note that this only happens if Thunderbird is set up in a particular way. You may not notice it every time. But there is a definite problem if you check the message syntax against what it should be in the RFCs. I can supply copies of the problem messages if required.

Thanks for your help. Bob