Mercenary Rarity Culler Not working

I have turned my mercenary into a rarity culler... turns out it just doesnt work or is so minimal it is not noticeable. Even with 400+% rarity on merc i am not seeing a difference in gold drops, uniques, etc. Running rogue exiles w/ titanic and they dont even drop a single unique after being culled w/ 450% rarity does not seem right. This has to be a bug, GGG pls fix!

I have tried gravebind on merc and using southbound on myself (i cannot freeze). I have thousands of hours as MF in this game and this is not correct.

The problem is Gravebind range is miniscule, if they arent on top of the mob it won't work

I know how gravebind works, I also tried with southbound... have you seen anything of rarity working on merc? maybe im somehow accidentally freezing/killing even tho i legit cant freeze?

I have the same problem, "only" 300 IIR though.
But i dont seem to see any changes.

My merc runs obliteration orbs and have culling.
I have southbound.

Pretty frustrating bot seing a difference. they should have left out the rarity stat on the merc if it is not intended to work.....

Same for me. Please respond: Is it "by design" or should it be added to known issues?