ZHA changes how it assigns addresses to new Zigbee groups, reducing the chance that a supposedly removed light responds to a new group’s commands. A device that was offline during deletion can retain its old group address; the previous allocator promptly reused that address.
New groups receive a randomly chosen unused address instead. This also makes it less likely that Home Assistant restores a deleted group’s name, area or labels onto the new group. Existing groups keep their addresses, and reuse remains possible rather than being eliminated.
Companion checks reject duplicate group names, addresses already in use and invalid members before creating a group. Showing those specific errors in Home Assistant’s interface requires separate work.