1. Capitar's faction ability Legacy of Serrane does not appear to make caravans immune to attack (though the other features seem to work fine).  I had a caravan murdered by a roaming Sand Golem.

2. Sometimes enemy AI taunts the player by announcing the acquisition of certain technologies or whatever; I have twice received such taunts that say "We have -1610612736.  You have 1610612736.  Something to laugh about... or cry about."  The exact number was different in each case I believe (though the one in my example is one that I received).