I have the same problem but it's not a 'bug' isolated to 2.6.2+
I've had the same problem on other builds of the arcade but like you said it's not with all games - just some.
Sometimes you only see the high score for a game - even though other members have played - and you don't see your score unless it's the high score and the option to leave a comment isn't there.
Not sure what causes it - could be the way some games submit scores?
Not a major problem though because the score still submits