This is something Horemvor mentioned once needed to be aded to Engineers Ability so it matches with its description, I did it and appears to be working. Same thing might work for ideology if you want to try it yourself.
<EffectType>AsteroidDecay</EffectType>
<Scope>Global</Scope>
<Target>
<TargetType>Faction</TargetType>
</Target>
<BonusType>Multiplier</BonusType>
<Value>-0.5</Value>
Wait, you mean Engineers never actually give -50% asteroid decay bonus like it should to begin with? I tried with the Ideology and it give me the error report that this type of EffectType is not acceptable. Maybe I done something wrong or made a typo, but thank for providing me the command code, Karl.
*Got pass the error. I made a typo, but in the end, it didn't works. The moment I hover my cursor over Coordinate trait in Ideology menu, the game crash.