You are not the only one dealing with this issue. The upgrades seem to be broken in multiplayer mode of this game. I recently encountered this bug when I played online today and my SBs got smashed pretty easily due to the inabilty for the upgrade to start. This is incredibly annoying as the SB essentially becomes useless later on as it keeps its basic range,dmg,armor,shields and hull. SBs do not seem to be broken in the single player, but thats not what currently concerns people. At the moment they seem like glorified turrets that can be destroyed pretty easily.