JPython should be fixed. CPython should be fixed. Both behaviors are acceptable. In many cases, introspection yields different results. Where appropriate and possible, JPython will adhere to CPython's introspection behavior.
Some differences are acceptable.
JPython should implement CPython's -O option. Proper behavior here is still unclear. JPython uses different values for the IOError argument. Both behaviors are acceptable. Other attributes will probably never be supported in JPython due to its implementation of code objects as compiled Java bytecodes.