Batch API arrays in JSON requests of JSONL batch request file are overwritten to empty arrays in JSONL results #513
Description
we observe that requests submitted to Batch API through JSON files get their array fields set by user overwritten to empty arrays
request JSONL file we trigger batch job with:
{
"id": "ac28c5e3-4343-4979-a95c-85d1007279c3",
"product_id": "bamv6jcclawoo",
"image_candidates": [
"c744f8d2-a0b8-4cbb-9a62-2582d0bd40e8",
"d6436c35-ddc1-4662-b45f-c7672de2140e"
],
"request": {
"model": "gemini-2.5-flash",
"contents": [
.....in output JSON file we get
{
"image_candidates": [],
"product_id": "bamv6jcclawoo",
"id": "ac28c5e3-4343-4979-a95c-85d1007279c3",
"status": "",
"processed_time": "2025-09-12T10:20:34.175+00:00",
"request": {
"contents": [ user data for plain fields is getting preseved, but arrays are reset to empty. what makes it worse, there are no errors or warnings. there is no errors before we validate and submit job. there are no error or warning logs in GCP Console. it is silent data corruption.
please fix error, or block requests that have this. or have some warnings. it is very easy to loose data. and hard to debug this.