First deployment forced to Production despite --target=preview

Hello Vercel Team,

We are trying to deploy a Next.js application to a new, isolated Vercel project.

Issue: The first deployment is classified as Production even when explicitly using --target=preview.

Environment:

Vercel plan: Hobby
Project: taiwan-stock-ai-v31-isolated-preview
Current deployment count: 0
Production credentials: None
Git auto-deployment: Disabled
Deployment Protection: Enabled

What we have verified:

Multiple Preview-only CLI attempts were unexpectedly classified as Production.
All incorrectly targeted deployments were removed.
Local application validation passed (162 tests).
Dependency security audit passed (0 reported vulnerabilities).
Production runtime access is blocked by a fail-closed guard.

Our requirement is to create the first deployment strictly as Preview, without any Production-target deployment, including temporary bootstrap deployments.

We found the related issue: https://github.com/vercel/vercel/issues/17069

GitHub

CLI preview deployments are unexpectedly created with target=production · Issue #17069 · vercel/vercel

Vercel CLI version 55.0.0 (Node.js 24.15.0, macOS) Expected behavior According to the Vercel CLI deployment documentation, vercel deploy creates a Preview deployment and --prod is required for Prod...

Questions:

Is there an officially supported way to create the first deployment with target=preview?
Can this be enabled for an existing project with zero deployments?
Is there an official fix or workaround that does not require any Production-target deployment?

We have stopped all further deployment attempts until a supported method is confirmed.

Thank you.