Since all this data comes from the security side of the house, it might be that this inventory change alerting is not applicable to it. If its the inventory service itself that performs this triggering some how, then this might be the cause. Another possibility is that these fields are actually per detection. They're not just one set of fields. Maybe the alerting doesn't work in this situation.
I played around with alerting a bit and from what i experienced, i think it is true that if a value in the DB is updated by something other than the inventory service, then the inventory service does not log it. I turned on logging for "Last Vulnerability Scan Date" and then performed both a security scan and an inventory on a device. There was never a log for it. I also turned on IP address for logging. I immediately began seeing entries for it. So its obvious that not all things that one can "check" in the inventory history panel, are actually going to get recorded in the history table.