Unknow feature "attached group"

Hello,

The is something very confusing :
Some groups (but not replicated nor copied) appears inside the “inbox”.
It appears to be “duplicated” but it is not.

How to get rid and remove any unwanted items from my inbox?

regards

This item doesn’t have any replicants or duplicates, the popup shows only the location of the selected item (as that’s the only instance).

I’m not seeing a problem with groups in the inbox
Like any record, I can move or delete them

Why does the item appear to be duplicated?