Here’s a mystery:
The adverb says its MOD is [ LIGHT + ]:
Yet it modifies a VP (this is Ivan does.not ask who is coming in Russian, there is a negation adverb):
Here’s the LIGHT value on the VP, it is minus, as expected:
Why would this be happening?
The first thing I would check is which rule is combining the ADV and the VP…
It is adj-head-scop-phrase
Next step: is adj-head-scop-phrase actually identifying structures that contain the two values of LIGHT you identified?
Ah. Indeed, for some reason basic-head-mod-phrase somehow lost its LIGHT identity. I didn’t even suspect that could happen because it is such an old phrase and I have no recollection of touching it lately. But I suppose I did!