I imagine people are buying caps to rig them before Odyssey.
Could be it. I also understand many schools just got out for the summer, and something about the south heating up a bit.
Yesterday I saw a person asking to buy an Archon in a nullsec trading channel. There I heard a 1.6b sell price and 1.2b build price so not that far off from yours.The person looking to buy the archon was complaining all builders he had approached were facing a big demand all of a sudden and he would have to wait two months to buy his archon while he wanted one before the expansion.Nice profit margins though.
Im sooo glad I finished the research on the Archon first :)