Does the civ trait 'Engineering' actually work?

Q:  Does the Civilization trait 'Engineering' actually work?  It is supposed to decrease decay by 50% but a quickie test shows it does not.

Steps to Duplicate:

• Create a new game with any race that has an additional small world in their home system (I used Arceans).
• Colonize the small world (Hammer in this case).
• Check the decay, it was listed at 4% in the colony tooltip.  Checking the core world planetary input math also shows 4%.
• Create a new game with the same race, edited to have the 'Engineering' trait.
• Colonize the small world (Hammer in this case).
• Issue ---> Check the decay, it was still listed at 4% in the colony tooltip.  Checking the core world planetary input math also shows 4%.