When I highlight a verse in the bible, the highlight gets applied to the verse anchor (e.g. Luke 17:21), causing any commentary passage that has the same anchor reference to be highlighted. Note the behavior is seen only if the highlight anchor matches the commentary anchor exactly, so any commentary on 17:21 is fully highlighted, but a commentary on 17:20-21 is not.
The highlight should only be applied to the resource that is being highlighted, in this case, the Bible. It probably does make sense for the highlight to apply across Bible translations, but not commentaries.