Pushes to `main` stopped creating deployments since July 12 — other branches deploy fine - Help

Hi Vercel team,

My project's main branch stopped triggering deployments on Git push around July 12, while pushes to other branches (v2-development, wt2/scratch) continue to create deployments normally.

Project: ensemble-manager (team: emsemble-manager-s-projects, Hobby plan)
Repo: ensemblemanager/ensemble-manager (GitHub)
Production branch: main (confirmed in Environments settings)
Last main deployment from Git push: July 11 (~4:16 PM UTC, commit 6dd17a9)
After that, commits pushed to main (bc8dcdb, 9fb72a5, 5b722d0) created NO deployment at all — not failed, not skipped, simply absent from the list
Meanwhile v2-development / wt2/scratch pushes on July 12 all deployed fine

Already tried:

Disconnect / reconnect the Git repository
Uninstall / reinstall the Vercel GitHub App
vercel.json has no git/deploymentEnabled/ignoreCommand settings (only regions + crons)
Ignored Build Step is Automatic, Root Directory is ./
Commit author email is consistent and verified

Vercel's in-dashboard AI support confirmed from your deployment data that this "points to a webhook delivery or processing issue specific to the main branch" requiring backend investigation, but as a Hobby user I cannot open a support case.

Workarounds (Create Deployment with main / Deploy Hooks / manual redeploy) all work fine — only Git-push-triggered deployments for main are broken.

I'm preparing to launch a beta soon and would really appreciate a backend check on webhook event delivery for the main branch. Thank you!

Update — solved it myself. Root cause was NOT a webhook issue.

After introducing git worktrees, I started merging into main with git merge --ff-only. Since the branch was already pushed (and deployed as a Preview) before merging, the fast-forward made main's tip point to a commit SHA that Vercel had already deployed. Vercel treats deployments per-commit-SHA, so a duplicate SHA produces no new deployment (not failed, not skipped — simply absent). That's why only main was affected, why other branches deployed fine, and why an empty commit (a fresh SHA) deployed successfully.

Fix: merge into main with --no-ff so a new merge-commit SHA is always created, which triggers the deployment normally. No webhook/reconnect needed.

Final update — fully resolved. There were actually TWO separate causes:

The original "main not deploying" issue: I was merging worktree branches into main with git merge --ff-only. Since the branch was already pushed (and deployed as a Preview) before merging, the fast-forward made main's tip a commit SHA that Vercel had already deployed. Vercel deduplicates per commit SHA, so no new deployment was created. Fix: merge with --no-ff so a fresh merge-commit SHA is always created. Confirmed working (empty commits and direct commits with new SHAs deployed fine).
A second, unrelated issue that appeared afterward: one later commit still wasn't deploying even with a fresh SHA. Checking the GitHub commit status revealed the real reason — "Vercel — Deployment rate limited — retry in 24 hours". I had simply exceeded the Hobby plan's 100-deployments-per-day limit (code: api-deployments-free-per-day), largely because worktree parallel development multiplied my preview deployments. This resets after 24 hours.

So: not a webhook issue, not a GitHub App issue, and NOT caused by worktrees or merge commits themselves. Cause #1 was ff-only SHA duplication (fixed with --no-ff), cause #2 was the daily deployment rate limit. Lesson for anyone using AI agents / worktrees on Hobby: watch the 100/day deploy cap — limit Preview deployments to specific branches and group commits.

Thanks!