At first I thought this was how the new system worked because this is not the first time I have seen this Issue. I thought that when infusing duplicate gear of the same energy types, the type of energy had to match. I then infused a duplicate warlock bond with different energy types into each other and it cost glimmer, but then when I go to infuse duplicate Warlock Helmets together it costs me Upgrade Cores. Can somebody help me figure this out?