Hello,
1. caching - this may occur on many level - JoomSEF, Joomla, you webserver, some kind of proxy, client.... at all these levels there may be caching enabled; to make sure things are working correctly, you should test with all caching disabled
2. we had simmilar issue with JoomSEF not generation META data and that was caused because during JoomSEF installation, the directory permissions on server were not configured correctly, and the JoomSEF Metabot (which is a system plugin) was not installed due to this; therefore, please, make sure your permissions are correct and JoomSEF Metabot is installed correctly; if not, fix the permissions and reinstall JoomSEF