district 12 achievement triggers without the conditions being met

[king of nowhere]

I was trying to unlock the district 12 achievement, and I dutifully did all the districts and colosseum in one city. I was only missing spaceport, because I don't have the tech yet. But now I found out I got rewarded anyway the achievement. the date is today at the time when I completed the aerodrome, and i played no other games today anyway. So it appears that spaceport is not needed for the achievement?

two things that may have influenced:
- space victory is not activated
- I have built 2 neighborhoods, so I still have the goal number of districts.