I had already commented on another topic but it's worth sharing it in here as it seems more informative.
Sneak attack simply doesn't trigger for me.
Checked on Astarion at lvl 4, attacking a target from hidden (so, having advantage) doesn't add the damage bonus.
Build v4.1.83.5246
Melee
![[Linked Image]](https://i.imgur.com/jqucUtC.png)
![[Linked Image]](https://i.imgur.com/PtyrnJM.png)
Ranged
![[Linked Image]](https://i.imgur.com/PZl90cY.png)
![[Linked Image]](https://i.imgur.com/WGsSuOf.png)
As a software engineer myself I'd bet that it's a trivial issue, like that the event "leaving hidden status" triggers before the damage and thus doesn't trigger the additional sneak damage.