Unable to delete an empty and obsolete list

[kiwigander]

I'm running Astrid 3.9.2.3 on an HTC Magic (Vodafone NZ version).

A few months ago I created a list called "Pack for Gold Coast": a
packing list for a business trip.

Astrid created the list in duplicate. When I tried to delete one of
the duplicated lists, both disappeared, so I recreated the list (and
got two).

I no longer need this list, so I deleted it - except that only one
disappeared, and I'm stuck with the second, empty list, no matter how
many times I try to delete it. I get the message "List Pack for Gold
Coast was deleted, affecting 0 tasks", but "Pack for Gold Coast" is
still in the list of lists.

When I try adding a dummy task to the list, it is accepted, and "Pack
for Gold Coast" now appears twice in the list of lists (with one task
in each listing).

When I delete either of the duplicate lists with the single dummy
task, I am asked to confirm: "Delete this list: Pack for Gold Coast ?
(No tasks will be deleted.) - even though there is one task in each
list.

When I do delete the list, the message flashes, "List Pack for Gold
Coast was deleted, affecting 1 task." And I'm still stuck with a list
"Pack for Gold Coast" with 0 items in it.

How do I get rid of this list?