Do any moral realists say that subjective judgments also have moral truth, such that unreal facts can oblige or permit us to act in a way that we really usually shouldn't?
Moral realists believe (very roughly) that there is an independently existing moral reality; that some moral judgements are true by virtue of that reality; and that some moral judgements can be known to be true. (I use the phrase 'by virtue of' in order not to entangle myself in theories of truth; while a moral realist needs a theory of truth, s/he is not committed as a moral realist to a particular theory, e.g. the correspondence theory.)
Only such moral judgements are true for a moral realist; subjective judgements, e.g. judgements based purely on emotion or on some intellectual error are either no capable of truth (as perhaps in the case of emotive judgements) or are false (as perhaps in the case of judgements based on intellectual error.
I am talking very roughly but this is the essential picture. But now, while subjective judgements are not and cannot be true, they can still be binding. A moral realist can find a role for conscience. If I sincerely believe that X, even if X is not a moral truth, a moral realist can still accept it as a moral truth that I ought to (try to) do X since it is what I sincerely believe I ought to do.
There is or need be no inconsistency in this on the part of moral realism. Given the fallibility of human beings, it is reasonable that even error has its rights; and this can itself be a moral fact, true by virtue of an independently existing moral reality.
So, I don't think a moral realist can accept that subjective judgements have moral truth exactly, but s/he can recognise as a moral truth that even an erroneous conscience is binding : an agent who is sincere in his or her moral judgement, even if that judgement is subjective, is morally bound or obliged to (try to) act on it.