See HIVE-4432 and HIVE-4433. It's possible to work around these issues but a better solution is probably to roll back the "fix" and change the API to use a primitive type as the map key (in a backwards-compatible manner).
Follow-up to HIVE-4322 - make metastore API changes backwards compatible
Fix C++ Thrift bindings broken in HIVE-4322
SkewedInfo in Metastore Thrift API cannot be deserialized in Python