Moderately often, when I select "Mark Read" on a STOP READING markup, it appears nothing happens [I usually do this in a columnar view]. However, it does actually mark that as read in the reading plan, and in my normal view pane I see the update in visual markup.
I can force the columnar view to fix itself by scrolling pages back and forth a few times.
I'm using L4.2b SR-1 (4.22.5.1109)
EDIT: Here is the proof pic:
