Production deploys blocked with "does not support collaboration"

Hi Vercel team,
Every production deployment on my project has been blocked since June 3 with the error:
“The deployment was blocked because the commit author did not have contributing access to the project on Vercel. The Hobby Plan does not support collaboration for private repositories.”
Identifiers:
Team: srinis-projects-59780edc (display name: Srini’s projects, Hobby plan)
Project: nikihana-dashboard (project ID: prj_mIiuMZFR8lR24WWfAhvD5653xwMp)
Production domain: my.celeum.app
GitHub repo: nikihana/dashboard
Recent blocked deployment IDs: HH4xcCUH2, 6QKdY4cDM, 7TG3HgRkq
Last successful deploy: v1.01224 (commit c40418b, May 23 2026)
First blocked deploy: v1.01225 onward (June 3 2026)
What I’ve verified to rule out the usual suspects:
Team membership: I (nikihana@gmail.com) am the sole member of the team and listed as Owner.
Email match: My Vercel personal-account email (nikihana@gmail.com, verified, primary) matches my GitHub primary email (nikihana@gmail.com, verified, Google-connected) and matches the git commit author email on every recent commit.
2FA: Enabled on my Vercel account after seeing the warning badge.
Recent commits: The last several commits (e.g. 94fc5cc, 773c1ef, 91b3ec5) have author = Nikihana nikihana@gmail.com and no Co-Authored-By trailers. They are still blocked.
Project ownership: The project is inside the team; there is no second Vercel project on this repo (I deleted a duplicate earlier today and the block persists).
Nothing on my side changed between the May 23 working deploy and the June 3 break — I’m the only contributor, the commits look identical in structure, and the team membership is unchanged.
My questions:
Which identity exactly is Vercel rejecting on these deployments? The error names “the commit author” but my commits are authored by the team owner — please tell me what Vercel sees.
Is there a Hobby-plan enforcement change that rolled out between May 23 and June 3 that would explain this? If so, what’s the documented path back to working?
If the issue is historical Co-Authored-By: Claude noreply@anthropic.com trailers in earlier commits being counted as additional contributors, can you confirm? And if so, is rewriting history the intended fix, or is there a project-level setting I can adjust?
Thanks.