I thought it automatically gave him his next level in the tech if mine was higher, and nothing if mine was the same or lower. I have the tech which is being offered. How can you offer something you lack ? For example, I cannot offer a ruins tech that I lack because it is not in my give list. I cannot want ppb before physics two because I do not even know it exists.

Good guess, but no you STILL have not found the bug. Try trading with my brotherly partners. There are only five of them.