In https://universaldependencies.org/u/overview/complex-syntax.html#adnominal-clause-modifiers, "sad" in the sentence "She entered the room sad" is acl, not so far below in https://universaldependencies.org/u/overview/complex-syntax.html#secondary-predicates it is advcl. Perhaps the latter is correct, given this:

The result is that in She entered the room sad, sad is considered a modifier (not complement) of the verb, with the relation advcl instead of xcomp. (This was changed from the previous approach which analyzed the secondary predication directly with acl, because the nominal predicand is not always overt, and even when it is, the adjective does not really belong to the same nominal phrase.)