Question about "rndc flushname"

[bsfinkel at anl.gov]

On a mail machine I am running a cache-only DNS - BIND 9.6.1-P3.
When I dump the cache I see two lines:

     ; answer
     brainpower-austria.at.  6622    MX      5 mx1.bon.at.

I then enter

     ./rndc flushname brainpower-austria.at

But when I then look at the cache, I still see the MX record (with a
shorter TTL).  Why is the "flushname" command not flushing this MX
record from the cache?  Thanks.
----------------------------------------------------------------------
Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory          Phone:    +1 (630) 252-7277
9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
Building 240, Room 5.B.8             Internet: BSFinkel at anl.gov
Argonne, IL   60439-4828             IBMMAIL:  I1004994