Current patch (has been a bug since the start).

The 'Tech Park' improvement requires 3 Research Quarters.

However, in checking this Requirement only research quarters are counted.

Emblematic quarters which have "Count as Research Quarter" (e.g. Exhibition Hall, Robotics Lab, etc.) are not counted.

Replication: Place three emblematic quarters that have "Count as Research Quarter" in a city's territory, try to build Tech Park.