We have one case where the extended bundles do not see the configuration admin service. Interestingly the same application runs fine everywhere else, but just on a special environment (windows, ibm java inside Websphere) we have this problem reproducibly.
Using the system bundle context instead of the bundle context of the extended bundle in ConfigAdminTracker solves the problem.
Interestingly only the bundles started last (2 out of probably 80) see the configuration admin.
It could also be that a faulty service hook is involved, although I'm not yet aware of such a hook
Update: after some discussion, some issues in the framework have been identified, but also the SCR implementation is not 100% correct: as it is using the bundle context of the extended bundle, it might get a configuration admin which interface is not visible to SCR. Therefore it should revert to reflection to access the configuration admin.