serve-expired seems to break flush_zone

[Marc Branchaud via Unbound-users]

Hi all,

I have a simple forward-everything setup with serve-expired enabled:
        server:
                serve-expired: yes
        forward-zone:
                name: .
                forward-addr: X.X.X.X

If I use "flush_zone ." to clear the cache, I still get cache hits for 
supposedly-absent entries (dump_cache shows that the cache is empty).

When I turn serve-expired off, "flush_zone ." results in cache misses 
for flushed entries.

With serve-expired on, I can only seem to force a cache miss by 
explicitly flushing a name (e.g. "flush google.com").  I really want to 
clear the entire cache, though.

Is this an intended effect of serve-expired, or is it a bug?

Thanks!

                M.