Pass output as Json in User Task and get it in a custom connector

I have a User Task which consists of an output field as:
all_inputs_xpaths:

{
  "x_ntu_eai_id": "$.rfServices[?(@.service.serviceSpecification=='RFS_NTU')].service.serviceCharacteristics[?(@.name=='eaiObjectId')].value", 
  "x_kpn_service_identifier" : "$.serviceCharacteristics[?(@.name=='gopConnectionId')].value",
  "x_minimum_bandwidth_up" : "$.serviceCharacteristics[?(@.name=='minimumBandwidthUp')].value",
  "x_minimum_bandwidth_down" : "$.serviceCharacteristics[?(@.name=='minimumBandwidthDown')].value",
  "x_cgw_eai_id" : "$.serviceRelationships[?(@.service.serviceSpecification=='CFS_CGW')].service.rfServices[?(@.service.serviceSpecification=='RFS_CGW')].service.serviceCharacteristics[?(@.name=='eaiObjectId')].value",
  "x_rfs_id" : "$.rfServices[?(@.service.serviceSpecification=='RFS_LA_GOP_FTTH_PHYSICAL_LINE')].service.id"
}

I want to receive this json in my custom connector either as String or Json, but once in the input section of my connector I define the variable as =all_inputs_xpaths
it is coming as Context, and is received with the exception:

io.camunda.connector.api.error.ConnectorException: Error during json mapping

context is null.
I am not sure why, is there a different method to receive that Json variable? Thanks