X_IMPORT_TOO_MANY_ERRORS
Means
more rows were rejected than the import allows
Typical cause
the rows the schema or the format refused passed maxRowErrors (default 1,000; 0 stops at the first bad batch). The batch that crossed the ceiling is not handed to handle, and every rejection so far is in the errors-*.ndjson parts under the run's error prefix — line, field and rule, never the rejected value
Fix
x jobs show <id> --json names the error parts; read the errors-*.ndjson they list, repair those lines in the file, and re-enqueue with a new key