I have found an issue with the blueprint-cm module:
it doesn't integrate with possible implementation of org.osgi.service.cm.ConfigurationPlugin registered in the OSGi framework.
That interface allows to intercept ConfigAdmin properties updates, allowing to manipulate their content without persisting them anywhere.
A sample usacase can be a decrypt component that decrypts values on the fly.
The issue on blueprint-cm is with the current implementation of CmPropertyPlaceholder:
updated() is correctly forwarded the props param, containing eventual manipulation of registered ConfigurationPlugin instances, but that content is discarded. The event will trigger a reload of the whole blueprint context, that will fetch the configuration from ConfigAdmin directly, thus bypassing the plugin behavior.