In last 2 days I uploaded new versions of my two plugins on WordPress Plugin Directory but the "Last Updated" date didn't change for them. Because of that, those plugins didn't come into the "Recently Updated Plugins" list on directory. Here are the two plugins updated in last 2 days by me,
1. WordPress Post Tabs - Upgraded to versions 1.2 - http://wordpress.org/extend/plugins/wordpress-post-tabs/
2. Related Posts Slider - Upgraded to versions 1.1 - http://wordpress.org/extend/plugins/related-posts-slider/
I followed the same process that I usually follow to upgrade plugins since last 2 years but never faced this problem. Plugins versions are updated perfectly and users are able to upgrade to the latest versions from dashboard. But the date (last updated) on plugins directory listing is still the old date and that is not good for new users as they might think that the plugin author is not upgrading these plugins in recent time.