Currently Data import job will completes with errors if it was mapped with some values missing:
io.vertx.core.impl.NoStackTraceThrowable: {{}}}{{{}"errors":[{{}}}{{{}"message":"must not be null","type":"1","code":"javax.validation.constraints.NotNull.message","parameters":[{{}}}{{{}"key":"contributors[0].contributorNameTypeId","value":"null"}]},{{}}}{{{}"message":"must not be

This validation takes place when Instance is being created.

We should add validation that would fail the processing at the stage of Instance mapping