unexpected behavior for search

[Bhaskara Marthi]

Either I have the search syntax wrong or there's a bug somewhere.  Is this
not how to combine multiple tags?  The output of the first invocation shows
that there exist threads tagged both inbox and unread, but the second
invocation does not find them.
- Bhaskara

$ notmuch search $(date +%s -d 2012-02-09)..$(date +%s) tag:inbox | grep
unread
thread:000000000000ff28  Today 12:41 [3/4] Mac Mason, Bhaskara Marthi; I'm
getting a build failure (inbox unread)
thread:000000000000ec68  Yest. 09:32 [1/6] Gonçalo Cabrita| Ken Conley;
[ros-users] serial_communication release (inbox unread)
$ notmuch search tag:inbox and tag:unread
$
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