Comment 2 for bug 1603535

Indeed, PGPool is likely the underlying issue. It appears that even within a transaction, the SELECT, is pulling from a replica and missing the very recent UPDATE. I do not have a Postgres log of the problem, but I have watched action_triggers to follow the pattern occurring:
   http://pastie.org/pastes/10908453/text

From an osrfsys.log, I can see the rapid update occurring, where the state changes, and the template_output appears in the 2nd "reacting" state, then returns to null in the "reacted" state.
   http://pastie.org/pastes/10908383/text

I am currently testing a trigger on action_trigger.event, where BEFORE UPDATE, I perform the following:
  IF NEW.template_output IS null THEN
    NEW.template_output = OLD.template_output;

I'm not aware of cases where template_output should be returned to NULL. If they do exist, I'll have broken something.