This afternoon I upgraded to 3.0.5 from 3.0.4. I've been building this site for a while and activating and deactivating plugins as necessary. After updating, on two occasions I deactivated plugins and was unable to re-activate them because they were dropped from the plugins admin panel. To re-activate one of them I had to delete the plugin folder and then reinstall the plugin again. A few minutes ago I deactivated cforms and it disappeared from my interface; the folder still exists on the server.
Has this happened to anyone else? Could it be a bug in 3.0.5? All ideas welcome :)