Hi there,
I suppose because of limits https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/azure-subscription-service-limits#change-tracking-and-inventory
Services 250
On the other hand, you can enable collecting required events directly to log analytics workspace, and monitor the status of the service by using the Event table, instead of Change Tracking
This approach is described in this blog post https://cloudadministrator.net/2018/01/24/monitoring-windows-services-sates-with-log-analytics/