Think this is probably true. Personally, the only reason I have my salvage yard is to gear my followers, and I simply cannot deny that I got far more follower upgrade items from my level 2 than I do with my level 3. Heard the same thing from others aswell, so decided to go back to level 2, and I am getting follower upgrades far more often now. Maybe it'll get fixed in the future, but right now I really need to gear my followers so I can send them out on mission that will grant me some upgrades, and for that the level 2 salvage yard will help me the most.