I've noticed recently that on some older quests I have recently replayed that if the player skips (esc or tabs out) a conversation midway a conversation where the last block of dialogue sets a stage and objective that firstly and obviously the stage is not set and the quest does not advance, secondly the conversation cannot be reinitiated or continued. There must be some way to make the player complete the whole conversation in order to advance the quest or make that dialogue available again - I just don't know what it is. Help please.

Uh... just avoiding quiting a conversation could do, couldn't it?