ldap_simple_bind call blocks with SSL connection, when DS hangs

Hi,

We are using Mozilla LDAP C SDK 5.12 in our application. We are
currently switching from synchronous calls to asynchronous calls.

When Directory Server hangs, it is known that clients using synchronous
calls like ldap_simple_bind_s will hang/block in LDAP SDK calls.
Ideally, this should not be the behavior with the asynchronous calls
like ldap_simple_bind.

But, we are observing that when Directory Server hangs, our application
is blocking in ldap_simple_bind call when connection used is in SSL
mode.
Also note that, in the same scenario, our application is not blocking
when connection is in Open mode.
Is anybody observed such a behavior? Any insights on this problem are
welcome.

Thanks in advance,
Ramakrishna.