I agree that legilimensed Sprout's magic is activating the sense of doom. But the troll was not legilimensed, so there's no reason for the sense of doom to activate.
I may be wrong, but intuitively it seems that when Voldemort causes Sprout to cast a spell, that spell counts as originating from Voldemort, not Sprout -- and that is what makes it activate the sense of doom. Whereas the troll was acting on its own accord, and so didn't activate the sense of doom.
I think Solipsist was trying to say that if Voldemort using Sprout to cast a spell counts as originating from Voldemort, then if Sprout (or some other Imperiused individual) cast a spell on the troll's skin, then Harry shouldn't have been able to touch the troll. Before, it was assumed that Harry was able to touch the enchanted troll (its skin had been enchanted to resist sunlight) because Voldemort hadn't directly enchanted it (Harry can't touch things Voldemort enchants, see the broomstick escape from Azkaban) but used an Imperiused confederate. Now, however, it seems that using the Imperiused confederate does not negate the issues arising between Harry and Voldemort's magic.
New chapter!
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 104.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: