We could take a few different aproaches:

Move all the highlights to the left in a consistent spot

Use a transparent left border that changes to blue/green as necessary

Reduce the padding when adding a left border

Also possible to push the green bar out to the left into the open space

In T94430#1163461, @EBernhardson wrote:

Move all the highlights to the left in a consistent spot

The "all the highlights" in this option is related to the "new posts" blue-highlighting, as seen in this screenshot (from an unrelated task). Moving them all to a consistent vertical location, might be good? Not sure.