Hi,
have this Output Today (and before also) - see Pic- on BIS Calulator - Specialy Back Slot, Rings, Waist, Finger where Sim is Selecting Resi , Stamina and other Weired Items.
Specialy happens when making exclusions (like Shadowweave Boots) on BIIS List:
If you click the green “help” link next to the big Best in Slot section header (you would need to scroll up a tad in your screenshot to make it visible), it will bring up a 32-digit code that you can copy here that we can use to exactly reproduce your case.
It is difficult to debug from a screenshot – something strange must be happening to leave a slot blank.