Software Asset Inventory Still Showing Removed Software

We've recently removed some software from Windows servers to remediate identified server vulnerabilities. The software no longer shows on the server in the Uninstall dialog, but the Orion Software Inventory widget, as well as showing when querying Orion.AssetInventory.Software via SWQL. These nodes are polled via SNMP and the last Inventory Collection poll is current. Any ideas why this is not updating?