GitHub merge to Production branch did not trigger a Vercel deployment

I have a private Vercel project connected to a private GitHub repository.

The configured Production branch is main.

A pull request Preview deployed successfully through the normal Vercel Git integration. The pull request was then successfully merged into main, but no Production deployment was created for the merge commit.

I have checked the project carefully and found:

• no deployment for the merge commit in any deployment state

• no Vercel Activity event for the merge commit

• no Vercel commit status or check on the GitHub merge commit

• no GitHub/Vercel Production deployment record

• the Git repository remains connected

• deployment creation remains enabled

• main remains the configured Production branch

Previous merges to main have automatically deployed to Production normally.

I have deliberately not manually redeployed, promoted the Preview, created a Deploy Hook, or disconnected/reconnected GitHub because I do not want to mask the underlying Git integration issue.

Could someone advise what could cause a successful merge to the Production branch to produce no Vercel deployment event at all, and what the safest next diagnostic step would be?

I can provide the exact project ID, deployment details and commit SHA privately to verified Vercel staff if required.