Wait does indeed seem to hang the script on the 7400s. Removing it again.

smsts-post-action.ps1

@@ -170,18 +170,20 @@ if($SCCMPolicyCheck) {
 	log "------------------------------------------"
 	log "Request Machine Assignments - (ConfigMgr Control Panel Applet - Machine Policy Retrieval & Evaluation Cycle)"
 	Invoke-WMIMethod -Namespace root\ccm -Class SMS_CLIENT -Name TriggerSchedule -ArgumentList '{00000000-0000-0000-0000-000000000021}' -Verbose 2>&1
-	log "Waiting 5 minutes..."
+	#log "Waiting 5 minutes..."
 	#Start-Sleep -Seconds 300 
 	# Start-Sleep was hanging the script indefinitely on some systems (Latitude 7400)
-	ping "127.0.0.1" -n 300 | Out-Null
+	#ping "127.0.0.1" -n 300 | Out-Null
+	# ping-based wait is still hanging the script on the Latitude 7400s
 	
 	log "------------------------------------------"
 	log "Discovery Inventory - (ConfigMgr Control Panel Applet - Discovery Data Collection Cycle)"
 	Invoke-WMIMethod -Namespace root\ccm -Class SMS_CLIENT -Name TriggerSchedule -ArgumentList '{00000000-0000-0000-0000-000000000003}' -Verbose 2>&1
-	log "Waiting 5 minutes..."
+	#log "Waiting 5 minutes..."
 	#Start-Sleep -Seconds 300 
 	# Start-Sleep was hanging the script indefinitely on some systems (Latitude 7400)
-	ping "127.0.0.1" -n 300 | Out-Null
+	#ping "127.0.0.1" -n 300 | Out-Null
+	# ping-based wait is still hanging the script on the Latitude 7400s
 		
 	log "------------------------------------------"
 	log "Application Manager Policy Action - (ConfigMgr Control Panel Applet - Application Deployment Evaluation Cycle)"