The guy who knows best (Andrew) answers:
I’ve run across this a number of times; the behavior described here is present both in Rosetta2 and Rosetta3.
Yes: the normalization of the gaussian is omitted. I don’t know the history behind this, but have experimented several times by adding the gaussian back in. Strangely, it hurts rotamer recovery. For this reason, I haven’t tried to persuade the community to fix this behavior.
But you’re right: it’s not a true log-likelihood score since the integral of the probability over all chi angles doesn’t come to 1.”