Guy, thanks. I've been digging through the code a bit, and it appears that we're probably dying because the id_callback that PHP has setup is invalid in some way. The spot where we get the "in ??" is this:
CRYPTO_thread_id() returns the result of a dynamic function pointer which is in fact set during the php curl extension's initialization step to tsrm_thread_id(), but its possible this pointer has been invalidated in some way.
I'm going to go ahead and try to install Community-ID and see if I can reproduce this on Hardy.