A server MAY choose to stop processing as soon as a problem is encountered, or it MAY continue processing and encounter multiple problems. For instance, a server might process multiple attributes and then return multiple validation problems in a single response.
When a server encounters multiple problems for a single request, the most generally applicable HTTP error code SHOULD be used in the response. For instance, 400 Bad Request might be appropriate for multiple 4xx errors or 500 Internal Server Error might be appropriate for multiple 5xx errors.
Creating custom rule to follow JSON API specifications
https://jsonapi.org/format/#errors-processing
A server MAY choose to stop processing as soon as a problem is encountered, or it MAY continue processing and encounter multiple problems. For instance, a server might process multiple attributes and then return multiple validation problems in a single response.
When a server encounters multiple problems for a single request, the most generally applicable HTTP error code SHOULD be used in the response. For instance, 400 Bad Request might be appropriate for multiple 4xx errors or 500 Internal Server Error might be appropriate for multiple 5xx errors.