Yeah it was actually my intention that even if you had the essence equipped, excluding it would take it off and choose a different one… but there are a lot of checks in the optimizer that makes it a bit difficult to ignore something that you actually have equipped in-game…
For now you can do as Swol suggests and just remove that essence, import again, then optimize. I’ll see if I can make the optimizer handle it automatically though. The issue is that the optimizer really doesn’t like choosing a solution that scores worse unless it absolutely has to. In this case we would have to make an exception because your equipped gear is technically “invalid”.