In the Demonology skill set, using Infernal Contract, sometimes my denizens disappear once I summon something else (such as a diggle hunting pack, or a wyrmling). This does not happen with other summons, and it is indeed possible to have diggles or a dragon at the same time as denizens. You simply make sure the denizens are the last thing you summon. They don't always vanish on another summon, so I was wondering if this was a bug or intended feature. If it is intended, then why does it only happen randomly, and not every single time I summon other things?