I\'m building a new ship and i have that bug (actually, i have it on all the ships i ever built). So i can say it\'s not a problem on old files. I don\'t know much for blueprints as i\'m not really used to them. Anyway, it\'s a part of the load of bugs of the % system of the weapons. I\'m don\'t want and have time to write a big post so i\'ll just copy here what i already said on another bug topic :
Cannons and missiles with modifyed specifications (the % thingies that i use evrywhere because my cannons shot too fast) can randomly reset when logging out and coming back (One of the different cannons on the computer (if there are more of one, for more sets of weapons, each can bug some of it\'s weapons) most of the time, but can be all of them). And, while it\'s already annoying to have to reconfigure them evry time, reconfiguring may not work : The % change, but the weapon data next to it don\'t, so you have to log out and in again to fix it (Happily bugging more weapons). Also, modyfying a weapon (by adding or removing blocks) will reset it\'s specifications, wich is also quite annoying, but can be useful as it will debug one wich got the previous bug (specifications stuck).
And we need a way to tweak all the weapons on a computer instead of doing it one by one. When you have more than 4 weapons (wich often means 20 or more), doing it manually sucks, especially when they reset sometime because you were logging out, so you have to do it all again...