The "nothing works like it should" sounds like you've got a thread
raising an exception without reporting it or its getting caught in a
way that makes it silent. I looked at your code  little bit but didn't
see anything obvious like this, however.   I also would say that the
EventBroker may be the problem for situation 1).  if you have a thread
that locks a mutex and then raises an exception you could get a race
condition in there which would create situation 1).

Situation 2) ENOMEM can also be raised when a program is exceeding
ulimit parameters.

And situation 3) I dunno.  Your program shouldn't segfault at any
time,  let alone a random one. What version of the ocaml compiler are
you using?

HTH.

-jbs