Holdover bug from v1. 4:
Create Research Project, of type Engine (Ion Drive, 100%, 0. 8L/h, 100%, 10HS). Go to Research section of Economics, and delete the newly created project. Attempt recreation of project in the Create Research Project Window (Ion Drive, 100%, 0. 8L/h, 100%, 25HS), receive error on Function #1051: An item with the same key has already been added.
Holdover bug from v1. 4:
After starting a new game where you get Instant Research Points, the "Instant" button in the Research section of Economics doesn't disappear once you run out of Instant RP. And there's no check to ensure you have sufficient Instant RP to research a tech.