The code to convert the results of a jsonPathExpression on a Parameter only returns the first item from a JSON array, and returns NULL if the result of the expression was a JSON object or any other non-string value.

This code was copied from the IfPipe#jsonPathExpression evaluation where this makes sense. However, for the Parameters this might not make sense.

It might make more sense for Param#jsonPathExpression to always return the full result as a JSON object: all array values, or the entire JSON object.