Let us consider such a phrase:
Ashley and I disagree on this subject.
As far as I understand it means that Ashley and the speaker have different opinions on the subject. But is not there some ambiguity? I mean the following:
Ashley and I disagree [with Fred] on this subject.
That is, depending on the context, it may mean that Ashley and the speaker share an opinion and it is different from that of Fred.
Thus, can A and B disagree have two meanings as described above?