The response message is too generic if a given workflow input has more than one validation. Users won't have a clue where to start looking:

{"failedNodeId":"_jbpm-unique-1","id":"6c55cb30-ee9e-41d1-97e9-89e38d68cca6","message":"org.everit.json.schema.ValidationException - #: 2 schema violations found"}

"2 schema violations found" is too poorly; there's no clue where to look.

To reproduce, you can use this project:
https://github.com/ricardozanini/kogito-serverless-loanbroker/tree/main/loanbroker-flow

Just submit an input with two validation errors.