Invalid YAML produces ERROR: 500 Internal Server Error

Feeding the validator a non-valid YAML source produces a ERROR 500: Internal Server Error without any indications of the error.

Running locally I see a stacktrace. If would be nice if using the /debug option that this was returned as content.

in 'reader', line 73, column 3:
      cluster-id:
      ^
expected <block end>, but found BlockMappingStart
 in 'reader', line 89, column 4:
       session-id:
       ^

        at com.fasterxml.jackson.dataformat.yaml.snakeyaml.parser.ParserImpl$ParseBlockMappingKey.produce(ParserImpl.java:570)
        at com.fasterxml.jackson.dataformat.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:158)
        at com.fasterxml.jackson.dataformat.yaml.snakeyaml.parser.ParserImpl.getEvent(ParserImpl.java:168)
        at com.fasterxml.jackson.dataformat.yaml.YAMLParser.nextToken(YAMLParser.java:342)
        at com.fasterxml.jackson.databind.deser.std.BaseNodeDeserializer.deserializeObject(JsonNodeDeserializer.java:212)
        at com.fasterxml.jackson.databind.deser.std.BaseNodeDeserializer.deserializeObject(JsonNodeDeserializer.java:218)
        at com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer.deserialize(JsonNodeDeserializer.java:62)
        at com.fasterxml.jackson.databind.deser.std.JsonNodeDeserializer.deserialize(JsonNodeDeserializer.java:14)

Start by tracing how malformed YAML reaches the validator and how the /debug option formats errors; the issue's stack trace identifies Jackson's YAML parser as the failure point. Confirm that invalid YAML returns its diagnostic content instead of only a 500 Internal Server Error.