Assertion in ares_cancel.c on channel->queries_by_qid check

Hi,

I've got similar assertion fails during ares_cancel and ares_destroy calls:
Assertion `ares__is_list_empty(&(channel->queries_by_qid[i]))' failed
(../c-ares-1.9.1/ares_cancel.c:48)
Assertion `ares__is_list_empty(&(channel->queries_by_qid[i]))' failed
(../c-ares-1.9.1/ares_destroy.c:65)

Could it be due c-ares API misuse? I didn't find any problems in
queries_by_qid cache related logic. I use c-ares 1.9.1 with curl-7.19.6.

-- 
Yours faithfully,
Evgeny Feoktistov.