Better upgrades using BiB when locking certain items

Snapshot ID: 842bfaee71404f349f53fb3b1c5f28c6

When i try BiB, it suggests a loadout.
But when i lock certain items, in my case, specifically Unguent Caress in Off-Hand, and Band of the Ancient Dredger on finger two, then reoptimize, the upgrade is significantly larger.
It jumps from a +18.66% DPS to +22.81% DPS when locking in those items.

Am i doing something wrong? Am i missing something, shouldn’t the BiB feature have selected the latter load-out from the get-go?
Both options keep me under corruption cap, and as far as i can see i don’t force any stats otherwise.