When a format is redefined an error should occur informing of the duplicate definition. Currently, if there is a defineFormat using the same name as an existing format (i.e. daffodilTest1) there is no error and the newly defined format is not used.

See test redefinedFormat:
daffodil-test/src/test/resources/edu/illinois/ncsa/daffodil/section05/simple_types/WhiteSpace.tdml
daffodil-test/src/test/scala-debug/edu/illinois/ncsa/daffodil/section05/simple_types/TestSimpleTypes2.scala