if they are currently active but not being inventoried then it means that the agent has probably been installed and is sending a heartbeat to the inventory server, but a snowpack file hasn't been sent yet. In Citrix this is probably because you haven't configured things correctly. To enable SLM to gain info in a Citrix environment I'd suggest the following:

1. Configure the Citrix SIM connector
2. Ensure the agent.config file is updated on the gold image to ensure the agent knows it is running in a VDI environment -  <Setting key="env.is_virtual_desktop_infrastructure" value="true"/>
3. Ensure this logout script is setup for all the citrix sessions to ensure that the inventory file is sent before the session is terminated

.DESCRIPTION

   This script will start the scan of the agent and send the inventory file

   when the user logs off from the VDI.

.NOTES

   AUTHOR: Iwan van den Hoek, Snow Software

   LASTEDIT: 2018-11-13

   VERSION: 1.1

   PREREQUISITE: Powershell version 3.0 or higher

.LINK

   http://www.snowsoftware.com/

#>

function Start-SnowAgentVDI {

   [CmdletBinding()]

   Param(

       [string[]]$AgentName  )

   if ($env:SNOW_AGENT) {

       $AgentName = 'SnowAgent'

       Write-Verbose "You are running the $($AgentName) and this is a version 5 or higher agent "

       $Process = Get-Process | where {$_.Name -like "$AgentName*"} | Select-Object -ExpandProperty Name

       $SnowAgent = (Get-Process -Name $Process).path

   }

   elseif ($env:SNOW_INVENTORY_HOME) {

       $AgentName = 'Client'

       Write-Verbose "You are running the $($AgentName) and this is a version 3 agent "

       $Process = Get-Process | where {$_.Name -like "$AgentName*"} | Select-Object -ExpandProperty Name

       $SnowAgent = (Get-Process -Name $Process).path

   }

   if ($SnowAgent -like '*Snowagent*') {

       $Send = "send"

       $scan = "scan"

       Measure-Command {     

           Write-Verbose "The $($Process) is scanning the system and will send the file"

           & $SnowAgent $scan

           & $SnowAgent $Send

       }

   }

   Elseif ($snowagent -like '*client*') {

       $Send = "-send"

       $scan = "-scan"

       Write-Verbose "The $($Process) is scanning the system and will send the file"

       Measure-Command {

           & $SnowAgent $scan

           & $SnowAgent $Send

       }     

   }

}

Start-SnowAgentVDI -Verbose

You can read a little more about this here - https://community.flexera.com/s/article/UserGuideSnowInventoryAgent6forWindows

Thanks

Adam