Some problems I've noticed while using 2-column mode with user picture turned off, on Win 8.1:
When the start menu reaches the top of the screen (lots of pinned or recent items):
-The main menu scroll buttons (for pinned items/recent items) double in height after applying changes in the settings menu.
-When this happens, the top menu item in the second column (i.e. after the column break but before the column padding) becomes inaccessible if you scroll down through the pinned items. Scrolling back up to the top makes it accessible again.
-Restarting CSM doesn't fix the problem, but restarting the computer does.