With the original firmware, version 1.3 (latest), it seems that when I first touch the scrollwheel I need to move a bit before scrolling starts. That initial move is farther than the move needed to scroll from one item to the next. That's probably what prevents button presses from activating scrolling.
It also seems like I have less of a problem with ignored button presses with the original firmware, but it's hard to be certain because it's rather rare either way and there are different patterns of button use depending on the firmware.