Any blend that has an ammonia smell from the lit bowl. The harshness is most perceptible during retrohale. This seems to occur more often with higher nicotine content.
I rehydrate Picayune & age it 6+ months; it becomes smoother & richer than when fresh & crunchy dryFor me Picayune is harsh for sure. Dark Bird’s Eye is pretty harsh but not as bad. For me the test is the retrohale.