I'm getting a duplicate of the original sacrificed infusion whenever I use the upgraded item as a new sacrifice for another one.
So for example, I infuse a Daybreak into an enchanted sword
When I infuse *that* enchanted sword into another weapon, the enchanted sword disappears like normal, and the targeted weapon gets upgraded, but I also get a fresh Daybreak in my inventory. I can keep chaining infusions into worthless items like this to duplicate it repeatedly.

The other thing is that the Wand of Frosting has disproportionately high infusion power (420) for how easy it is to get early game. I guess it's due to how the weapon works in some specific world seeds.