I’ve just had an interesting bug. It’s not important, but you may want to know.
I was doing an echo. At the end, I called the portal and entered it. Just before, I summoned my skeletons. They are three, and the skill is set so that I summon the three at once.
I heard the summoning twice then the animation of the portal started.
When I arrived in Echo of a World, I had two skeletons with me but the game told me I had three. So I suppose the third one was still in the echo, which is probably now a deleted instance.
I did not wait for him to eventually come by another way, I just resummoned the pack and everything is OK. But I find it rather interesting that the game can consider as existing a skeleton that has disappeared in a closed echo.