In classic Discovery setting the Asset Status of a record to Disposed will free up that client agent license and ensure the software for that asset no longer shows in any software reports. Only the hardware details of the machine are displayed.
In HEAT Discovery setting the status of an asset to Disposed does not remove the asset's software from the Software Inventory workspace or software-related reports.
This issue is logged with our development team as issue RM 234218. There is no workaround at this time.