If there is a pending edit to a release that also displays in the sidebar (e.g. a label), it doesn't highlight the label itself in the sidebar. This makes it easy to miss a relevant change. For a concrete example consider the release:
I have a made an edit to correct the label here:
However, because "Volition" isn't highlighted as being changed in the sidebar, it means that people won't easily spot that the label might not be correct, leading to editors taking the label as being correct, when the release is actually being changed. For example, I also updated the discogs label to point to the new (correct) release in http://musicbrainz.org/edit/15850366. However, it was voted down by another editor who thought that the label was correct. These kinds of issues would be easier to spot if the label in the sidebar was highlighted as having a pending edit.