Custom converters not used for map keys

I have an enum with rather long names and shorter per-value "tags" that I want to use for serialization. I've implemented a Converter pair that maps the values back and forth. They work properly when saving a Set of the enum.

However, when saving a Map<MyEnum,?>, the converter method is skipped; the enum's name is still used as the map key saved to Mongo. This would be frustrating but work-aroundable, but the proper converter is applied on reads. This means that when I save an object with a non-empty map and immediately attempt to read it, I get an exception when calling the read converter (since it's being supplied an invalid argument).

The problem appears to be at MappingMongoConverter:644, where the conversion service is explicitly skipped. This means that converters are applied to all types on read, and to all instances except map keys on write.