Hi Rodrigio,
It can be a similar problem, if you don't see any errors in the Notification Server Log during processing of the NSE files. To make sure in that you can install some new software on problematic client machine and execute Full Software Inventory on it. If it will resolve the issue it's the similar problem but with different Data Class.
If it will not help, please make sure that there is not errors on client side during Full inventory.
Also please verify next Items:
In Advanced options of the Collect Full Inventory policy make sure that "Send inventory changes (deltas) only" option is not checked.
Please open NSE files which you get on problematic client machine and try to find there any data about some software (name, version, etc.) Is it there?
Also you may verify "C:\Program Files\Altiris\Altiris Agent\Agents\SoftwareManagement\data\SoftwareCache.xml", it should contain data about discovered software. After full inventory data from this file is sending to Notification Server.
Regards,
Dmitri