The doom-sense could have a lot to do with both the strength of the magic and the degree to which it inherently clashes with the senser’s inclinations or goals.
To me, it seemed that it scaled with their current mindsets and actions, with stronger being the more they contrasted.
Consider how strongly it was felt when Harry’s “anti-death-ness” was particularly strong (e.g. after Harry killed his first Dementor) or when Voldemort’s desecration of death was higher than normal (e.g. when he makes Inferi).
Inversely, look at weak the feeling is when their current mindsets are not so opposed (e.g. when Quirrell was in zombie-mode in ch 49, because he practically lacked a mind at those times).
Though, the zombie-mode in ch 26 was still fairly strong, which could imply that zombie-mode isn’t as big of a determinant as I initially suspected. It might well be another piece of evidence towards the importance mindset, however, as that ride ends with Quirrell leaving to “set something into motion,” which is certainly ominous coming from Lord Voldemort and may well have been something Harry was inherently set against. I don’t remember if we found/figured out what he was doing there.
Taking this into account, the lack of doom-sense during the transfiguration would simply be there not being much of a mindset left.
Though I fear I may have strayed from the original thrust of your post.
To me, it seemed that it scaled with their current mindsets and actions, with stronger being the more they contrasted.
Consider how strongly it was felt when Harry’s “anti-death-ness” was particularly strong (e.g. after Harry killed his first Dementor) or when Voldemort’s desecration of death was higher than normal (e.g. when he makes Inferi).
Inversely, look at weak the feeling is when their current mindsets are not so opposed (e.g. when Quirrell was in zombie-mode in ch 49, because he practically lacked a mind at those times). Though, the zombie-mode in ch 26 was still fairly strong, which could imply that zombie-mode isn’t as big of a determinant as I initially suspected. It might well be another piece of evidence towards the importance mindset, however, as that ride ends with Quirrell leaving to “set something into motion,” which is certainly ominous coming from Lord Voldemort and may well have been something Harry was inherently set against. I don’t remember if we found/figured out what he was doing there.
Taking this into account, the lack of doom-sense during the transfiguration would simply be there not being much of a mindset left.
Though I fear I may have strayed from the original thrust of your post.