+1 for autosave before dream scenes while resting.
I thought the dream scenes only occur after you use [Illithid] Dialogue options or Illithid powers? I never got dreams because I refuse to do either, as I'm pretty sure it's the tadpole because the more you use the powers, the more dreams you get, and eventually a "True Soul" you become.
This may be true, but keep in mind that it is just triggered by LR. So, for example, if he used the Illithid Power one or too many times during the Goblin fights and then rests (you have to do that if you want to fight Minthara in the Druid Grove) et voila dream scene. By the way, I had the same problem, but I didn't use any Illithid Power. The last time I used it was when fighting Auntie Ethel, but only once with my Battelmaster to pull her closer to me to increase the hit chance.
However, I mean that after fighting with Auntie Ethel and Kagha, I did one LR before infiltrating the Gobbos. But no dream scene. Anyway, I didn't use any Illithid Power or Illithid Dialogue after Auntie Ethel, but the dream scene was triggered the next LR I did after I purged the Goblin Camp and right before facing Minthara at Druid Grove.