I assume this is a known issue, but something (usually during combat) seems to be able to corrupt history segments (usually 100 ticks or so and I think it has to do with a creep dying). This is infuriating as it often leads to thousands of uneventful ticks, then the 100 ticks where ur siege code fks up, u have no history to review, then after the blackout u just see gravestones.
#Fix whatever causes the no data history ticks
polar reef
drifting cipher