Correct Admiral! I had this feeling because all my neighbors changed in leadership at least one, sometimes more, except for Man that I contributed to annihilate...
Actually it happens in all my games. Sometimes you design a whole strategy around your diplomacy and this fires back on you. Once I even let an ally forge key artifacts to confirm friendship and 3 turns later leadership changes and I get a DoW nonetheless! In an other game my trustworthy ally, whose border I did not garrison while committing to a war far away, suddenly attacks me in full strength after being turned AI... So betrayal set apart, one should always expect anything from anyone...
At least the First and Last Emperor of Shinumaya remains true to His Words in this chaotic world! I think this in itself is a mark of godhood
