For example, when watching revision 2 in this revisions list in the side-by-side mode, word "answer" marked as deleted on the left hand side and as added again on the right hand side:
If we switch to the side-by-side markdown mode no "answer" word is highlighted at all (correctly):
bugtag to your post because it's a bug, not a FR. – αλεχολυτ Dec 12 '16 at 4:23