HTMB Drop Mechanics

Hi. Im doing some HTMBs on D or VD to see if loot drops even if everyone in the party already has it (thinking of having LS people come and grab it from pool). So far stuff is not dropping. It's mainly bog standard stuff like Cessance Ring and Ginsen.

Also noticed that Apate Ring will not drop from Selkit if all in party already have it. I've done maybe 60 fights to test that one XD.

Just wondering if this is a known mechanic to stop naughty people like me, or if it's just my imagination and bad luck.

If everyone in the party has the item and it's rare then it will not drop. This is known.
If you however send the item to yourself and don't pick it up from your inbox (so you don't have it on your char) it can appear in pool (since you "don't" have it).
GL farming

Great thanks. Thought that might be the case.