Recent optimization and error reporting changes in CasManager_impl in the 2.6.0 uima-sdk uncovered a uima-as aggregate bug in code which tries to merge type systems from delegates where one of them is a remote CM.
See UIMA SDK JIRA:
The new uima sdk code complains if addMetaData method is called after CasPool is created. It turns out that the UIMA-As aggregate creates a Shadow CasPool for its remote delegate CasMultiplier before the type system is merged.
Fix is to move the code that creates Shadow CasPool beyond where the merge occurs. After successful merge create the Pool.