How to trigger a nightmare/vision during long rest ["Good" Dark Urge]?

[Annie Other]

(Probably don't need spoiler tags, as I am still very early in the game.)

Will something like this even happen?

So far I only explored parts of the beach, found the chapel ruins (but avoided going in, somehow rings an alarm bell), a door that looks like an entry to a dungeon (avoided that one, too for now, as no one in my team is good at fighting) and found a fire patch I seem to be unable to jump over (no one in my team has more than 10 STR, but I forgot to check if Gale has a helpful spell prepared, maybe he has).
Got that scene while looting the mangled fisherman, of course (also "talked" to the cultists in the Prologue earlier). Found Shadowheart, Astarion and Gale and talked to all of them. Admitted my condition when ever allowed. Talked to that dying Mind Flayer. Fought a couple Intellect Devourers.

I didn't need to rest just yet (maybe to adjust spells), but I tried just to see what happens.
Talked to my companions. Talked to them again. Not that much, but Shadowheart may be jealous of Gale already?
Then I went to sleep.
And was a bit disappointed that nothing happened, nothing at all.
Shouldn't I have a nightmare after the dark thoughts and memory flashbacks I already had?
My personal logic suggests that I should. I certainly would have terrible nightmares or lay awake all night if I was in such a situation.

Do I need to get and solve a sidequest first? Trigger another DU-specific dialog?
I don't know what to do next. I'd love to see the story progress and get more of these dark thoughts and memories. And maybe a nightmare or vision.

[Doomvora]

The cutscenes during long rest happen after specific points in the game.

Aka progress the main story and do any personal quests.

[Lokieys ★]

first nightmare is after you make a decision with the druid grove I think(help or kill). It involves a bard. won't say more.

[Shyba]

afaik you can't get the first "dark urge" scene till you have been to the grove. you don't need to interact with the NPC just have BEEN to the grove (they magically knows you regardless lol...)

[Annie Other]

OK, thanks.
Hopefully I'll get some more dialog lines on the way.
(I still would have loved to see a single line, at least, about having slept badly and having had bad dreams.)

[Shyba]

Originally posted by Annie Other:

OK, thanks.
Hopefully I'll get some more dialog lines on the way.
(I still would have loved to see a single line, at least, about having slept badly and having had bad dreams.)

you get those in dialogs (those Fantasizing about doing X lines)