[couslee]

I noticed something, that may answer the problem here. (squash that bug)
Now, the game and race that started this thread is long gone.
The Simultaneous game before my current game is also gone but I am still using the same race file. In that game, I did save the empire with designs.

That being said.

In my new current game, when I click on the stats option, it shows I have "in service" the same number and type of ships that I had in my abandoned game.

Perhaps, the game's failure to delete those designs is due to the empire file still showing ships "in service" of that type.

As I said, the old game is gone, so i can't go back and try different workarounds, like re-saving the empire file on turn .9. But this is a strong possible explanation imo. I will be looking more into this in my current game. I will have to re-create the bug, and then try a workaround. if that fixes it, then fixing this bug in the next patch should be easy for MM.
(if I don't get killed trying to do someone elses job.) I would like to play the damn game, not bug hunt it. It will take about one more major irritation and off my HD it goes.