Smart Mailbox submailboxes are blank

No, this is a mailbox provided by default. I'm not sure what's going on. Does the problem persist?

Try sending me this file:

~/Library/Application Support/MailMate/Mailboxes.plist

That'll make it easier for me to see if the mailbox has been changed in some way.

Yes, the issue persists.

Here's the mailbox entry in the .plist file. Other smart mailboxes that use submailboxes aren't seeing this.

If I remove the partitioningFormatString field and restart MailMate, the submailbox labels (albeit the default ones) show up as expected.

nall.

            {       filter = "list-id.identifier exists";
                    name = "Mailing Lists";
                    parentUUID = "MAILBOXES";
                    partitioningFormatString = "${list-id.description:${subject.blob:?${subject.blob:/capitalize}:${list-id.identifier.final-level}}}";
                    partitioningHeader = "list-id.identifier";
                    set = "ALL_MESSAGES";
                    showSingleChild = :true;
                    uuid = "MAILING_LISTS";
            },

Benny,
I do notice that removing the .final-level suffix on that else term causes the labels to be displayed.

Thanks for the details. Maybe the problem is related to the List-ID header of your messages. Could you select one or more of your messages and then use “View ▸ Show Raw Source” to get me some examples of this header?

A-ha! I'd missed that there were some at the bottom that don't disappear.

I can't paste the item as-is, but here's an obfuscated version of one of them:

List-Id: <A_B_C$@sub.domain.com>

Also, this one disappears:

List-Id: <aBCD@sub.domain.com>

However, this one doesn't disappear:

List-Id: <A-B-C-D@sub.domain.com>

I'm stumped. Further, I see some mails in submailboxes where the submailbox name doesn't appear anywhere in the raw mail text.

Let me know if I can provide any more info.