I have additional information. I did a test with another admx ingestion (Google Chrome admx) After the ingestion was succesfully implemented i removed the configuration profile. The i watch the eventviewer what would happen. In the eventviewer i noticed remove the policy would not remove the admx ingested policies. Instead there was a error. So somehow it is impossible to remove or change an ingested admx. Is this a know bug? MDM ConfigurationManager: Command failure status. Configuraton Source ID: (E60DE700-BEFA-43C6-90F3-8F8906C7BB83), Enrollment Type: (MDMDeviceWithAAD), CSP Name: (Policy), Command Type: (Clear: first phase of Delete), Result: (./Device/Vendor/MSFT/Policy/ConfigOperations/ADMXInstall/Chrome/Policy/ChromeAdmx).
I need to investigate how to correctly overwrite or delete an existing ingested ADMX policy, but in the meantime a working way is to ingest the new ADMX with a new identifier and then address the new one during configuration: