Codecov status checks significantly delayed after successful upload

[dalnoki]

Summary

After a successful coverage report upload (HTTP 200 from GCS), Codecov intermittently takes 25 minutes to 2+ hours to post a status check back to GitHub. This blocks our Merge Queue, stalling all PRs stacked behind the affected commit.

Steps to Reproduce

1. Upload a coverage report via codecov-cli
2. Observe HTTP 200 response confirming the file was written to storage
3. Observe that no GitHub status check appears for an extended period (25 min–2+ hrs)
4. Note that the Codecov dashboard shows the commit as "waiting for head commit" even when full coverage data is already visible for that SHA

Expected Behavior

A GitHub status check should be posted shortly after the upload completes.

Actual Behavior

The status check is delayed significantly. In some cases it eventually arrives; in at least one case a re-upload ~2 hours later was required before a status was reported.

Impact

• GitHub Merge Queue is blocked for all PRs stacked behind the affected commit
• Issue is intermittent but recurring, affecting multiple PRs across multiple days
• The Codecov dashboard shows an inconsistent state: "waiting for head commit" when data for that SHA is already fully visible

Environment

• Codecov CLI (upload via codecov-cli)
• GitHub Merge Queue

[linear]

CCMRG-2139