I think as sure the novels flat out say immune but I’m not doing a full reread to check plus again.
Dragons of Spring Dawning has this passage when Tas approaches the Shoikan Grove
"I should go back, Tas thought, but he couldn’t. The curiosity that did more than anything in the world to reduce the kender population kept drawing him forward.
Tas came to the edge of the grove of oak trees and—here—his heart almost failed him. Kender are normally immune to the sensation of fear, so only a kender could have come even this far. But now Tas found himself a prey to the most unreasoning terror he had ever experienced. And whatever was causing it was located within that grove of oak trees.
They’re ordinary trees, Tas said to himself, shivering. I’ve talked to spectres in Darken Wood. I’ve faced three or four dragons. I broke a dragon orb. Just an ordinary grove of trees. I was prisoner in a wizard’s castle. I saw a demon from the Abyss. Just a grove of ordinary trees.
Slowly, talking to himself, Tasslehoff inched his way through the oak trees. He didn’t go far, not even past the row of trees that formed the outer perimeter of the grove. Because now he could see into the heart of the grove. Tasslehoff gulped, turned, and ran."
Dragons of Winter Night
"“Get out!” the mage thundered. “All of you!”
“I was ordered not to leave and I’m not—” The knight reached for his sword, but Fizban whispered a few words. The knight slumped to the floor. The gnomes vanished from the room instantly, leaving only Gnosh, wringing his hands, his face twisted in agony.
“Come on, Gnosh!” Tas urged. “I’ve never seen him like this. We better do as he says. If we don’t, he’s liable to turn us into gully dwarves or something icky like that!” Whimpering, Gnosh allowed Tas to lead him out of the room. As he stared back at the dragon orb, the door slammed shut.
“My Life Quest …” the gnome moaned.
“I’m sure it will be all right,” Tas said, although he wasn’t sure, not in the least. He hadn’t liked the look on Fizban’s face. In fact, it hadn’t even seemed to be Fizban’s face at all—or anyone Tas wanted to know!
Tas felt chilled and there was a tight knot in the pit of his stomach. The gnomes muttered among themselves and cast baleful glances at him. Tas swallowed, trying to get a bitter taste out of his mouth."