Is that normal when we do upsertMany(), ids are added even if there already exist?

[Jukien]

Hello,

I'm trying to use selectAll() feature but I get more elements that there is in the entities array in the store.
I found that I have more ids than the entities. Some ids are duplicated. Is that normal?
When we do upserMany(), if an id already exists, it shouldn't be add no?

[Jukien]

I saw that it's an issue #796