lei q -tt doesn't work properly?

[Maxim Mikityanskiy <maxtram95@gmail.com>]

Hello,

I'm trying to use the -tt flag to download the whole thread, but mark
the actual matching emails as important. I'm not sure if I'm doing it
incorrectly, or maybe there is a bug in lei.

According to the man page:

--cut--

-t  Return all messages in the same thread as the actual match(es).

    Using this twice ("-tt") sets the "flagged" (AKA "important") on
    messages which were actual matches.  This is useful to distinguish
    messages which were direct hits from messages which were merely
    part of the same thread.

--cut--

I'm using this command, for example:

lei q --no-save -a -o /tmp/lei-test -I 'https://lore.kernel.org/all' \
    -tt 'a:syzbot AND rt:2023-01-01..2023-01-07'

What I expect to see is at least one flagged email in each thread
(otherwise why would this thread by downloaded), however, instead, most
of the emails are not flagged, that is, the whole threads don't have any
flagged email (although they clearly have emails from syzbot, which
caused the match). Occasionally, some emails are flagged, for example,
these two:

https://lore.kernel.org/all/87wn621hmp.fsf@toke.dk/
https://lore.kernel.org/all/20230103081308.942805751@linuxfoundation.org/

It looks as if the match works correctly, but the -tt option fails to
mark most of the matched emails as important, except a few that actually
got marked (I couldn't find a pattern here). It's also not consistent,
for example, after I removed /tmp/lei-test and restarted the lei q
command, I got many more important emails, almost in each thread, but
there were still threads without flagged emails.

I'm checking the flags with mutt.

Does anyone know what could be the reason for such behavior?

Thanks,
Max