Found the problem. It's in Anomalies_ScenarioTriggerSetDefs.xml
<Modifier>
<EffectType>CultureMerciless</EffectType>
<Target>
<TargetType>Faction</TargetType>
</Target>
<BonusType>Flat</BonusType>
<Value>3015</Value> [Should be 15.]
</Modifier>
I'll take a peak at the other Mega Event files for problems.
Edit: This one seems to be only file with the bug.