Glad it's fixed, although I am bit surprised that 2 constructors were generated for data class?
(and both then got @JsonCreator annotation). Neither was declared as synthetic at JVM level (I was guessing 0-param might be but did not seem to).

EDIT: Ah. Description specifically said the problem is/was that when default arguments are used, there is need for 0-param constructor to support defaulting. This seems problematic wrt specifying annotations if/when they are duplicated... hmmh.

Thinking about this further: it'd be good to know that in case of multiple constructors, some are secondary ones... but for now assumption has been that @JsonCreator must be explicitly selected. But somehow precedence needs to be established.

With JDK, there is the concept of "bridge" methods (Method.isBridge()) but same does not exist for Constructors unfortunately.