Unlike the addItem and removeItem commands, the addSoulGem and removeSoulGem commands don't display a message in the dialogue screen when they're called from dialogue result.

If a soulgem is used as a quest reward, this can be confusing to the players, because they might think that the quest is bugged and they haven't received any reward (see also https://www.tamriel-rebuilt.org/bugtracker/ember-keep-soul-swipe-quest-g...).

In every quest that does this, we add a MessageBox saying that a soul gem was added to your inventory to the dialogue result, except for https://en.uesp.net/wiki/Tamriel_Rebuilt:Deal_with_a_Devil, where this is missing from Absolon's Greeting 1 where he gives you a soulgem with a Dark Seducer soul.