Please make sure you have searched for information in the following guides.

• Search the issues already opened:https://github.com/GoogleCloudPlatform/google-cloud-node/issues
• Search StackOverflow:http://stackoverflow.com/questions/tagged/google-cloud-platform+node.js
• Check our Troubleshooting guide:https://github.com/googleapis/google-cloud-node/blob/main/docs/troubleshooting.md
• Check our FAQ:https://github.com/googleapis/google-cloud-node/blob/main/docs/faq.md
• Check our libraries HOW-TO:https://github.com/googleapis/gax-nodejs/blob/main/client-libraries.md
• Check out our authentication guide:https://github.com/googleapis/google-auth-library-nodejs
• Check out handwritten samples for many of our APIs:https://github.com/GoogleCloudPlatform/nodejs-docs-samples
• Check the API's issue tracker:https://cloud.google.com/support/docs/issue-trackers

Library Name

@google-cloud/bigquery

A screenshot that you have tested with "Try this API".

same issue was already reported for the Go client:googleapis/google-cloud-go#13786

Link to the code that reproduces this issue. A link to apublic Github Repository or gist with a minimal reproduction.

https://github.com/googleapis/google-cloud-node/blob/main/handwritten/bigquery

A step-by-step description of how to reproduce the issue, based on the linked reproduction.

1. Install @google-cloud/bigquery@8.2.0
2. Run any BigQuery query that involves timestamp fields
3. Query fails with: "timestamp_output_format is not supported yet."

A clear and concise description of what the bug is, and what you expected to happen.

v8.2.0 (published Feb 20, 2026) sendsformatOptions.timestampOutputFormat in query job requests.
The BigQuery API does not support this parameter and rejects the query with:

"timestamp_output_format is not supported yet."

This breaks ALL queries, not just timestamp-related ones. The same issue was reported
for the Go client on Feb 4:googleapis/google-cloud-go#13786

In v8.1.1, onlyformatOptions.useInt64Timestamp was sent, which works correctly.
The change is in build/src/bigquery.js lines 1413-1432.

A clear and concise description WHY you expect this behavior, i.e., was it a recent change, there is documentation that points to this behavior, etc. **

v8.1.1 worked correctly. v8.2.0 is a minor version bump which per semver should be
backward-compatible. Instead it introduces a parameter (timestampOutputFormat) that the
BigQuery REST API does not yet support, breaking all queries. The BigQuery REST API
documentation for DataFormatOptions does not reference this parameter.