Type XXI Radar Destroyed?

[UKönig]

I played stock SH3 and when I got my type XXI, the very same thing happened. Choked me up too because I could have saved those renown points for new torpedos or whatever.
I think the game wasn't expecting anyone to get that far and they (the programmers) didn't do their jobs properly. Rather than let you have a working radar system, they just "destroyed" it to preserve the integrity of the game.
If anyone else has a more accurate answer regarding the instant failure of a brand new system even before leaving port, I would also like to know...