I got nuked 2 hours after the war should have expired. The time I got nuked is certainly correct in game, as it came at least an hour before the "conflict expired" text showed up. 11:55pm on 4/27 is when the war SHOULD have ended, is much closer to after 4am 4/28.
04/28/2016 01:55 am Captain Nicholas Saint of Hudson Bay detonated a nuclear weapon in the nation of Gensokyo. The attack destroyed 1,774.00 infrastructure in the city of Higan and 2 improvements.. 04/27/2016 11:55 pm This conflict expired after neither side could emerge victorious nor agree to peace.
Basically the war ended later than it should have, and the timeline is a lying.