Playing a replay (Play --> Replay game --> choose a save) will make all blueprints that are global within the replay also global for the player.
Steps to reproduce (on a fresh install):
- Start a new game with replay enabled
- Blueprint something and put it in the global blueprint list ("My blueprints" on the right side), then save that map
- Quit the game and delete the blueprint-storage.dat file
- Restart the game and start a new map, after pressing B (or clicking the blueprint icon) you'll see that the blueprint is gone
- Replay the game you saved earlier
- If you now start a new game the blueprint is there, although you only replayed the game