On April 28, 2026, GitHub published An update on GitHub availability on its own blog. It gives an update in light of two recent incidents, which it calls "not acceptable," and sets out what the company says it is doing about its reliability. One of the two affected merge queue. Parts of the post follow, not the whole.
What the Post Says Happened
"On April 23, pull requests experienced a regression affecting merge queue operations," the post says. Pull requests merged through merge queue using the squash merge method "produced incorrect merge commits when a merge group contained more than one pull request."
"In affected cases, changes from previously merged pull requests and prior commits were inadvertently reverted by subsequent merges."
The post gives the reach. During the impact window, 658 repositories and 2,092 pull requests were affected. GitHub says it first shared slightly higher numbers "because our first assessment was intentionally conservative," and an editor's note says the post was updated on April 28 to update the number of repositories affected.
It also says what was not affected. The issue did not affect pull requests merged outside merge queue, "nor did it affect merge queue groups using merge or rebase methods."
A completed merge looks like the end of the job. Here the merges completed, and the commits they produced reverted earlier changes.
No Data Loss, and Process Failures
"There was no data loss: all commits remained stored in Git," the post says. The commits were there. "However, the state of affected default branches was incorrect, and we could not safely repair every repository automatically."
More details, the post says, are available in the incident root cause analysis. "This incident exposed multiple process failures, and we are changing those processes to prevent this class of issue from recurring."
Capacity, and the Status Page
The company says it started executing a plan in October 2025 to "increase GitHub's capacity by 10X," and that by February 2026 it was clear it needed to "design for a future that requires 30X today's scale." The main driver, it says, is "a rapid change in how software is being built," with agentic development workflows having accelerated sharply since the second half of December 2025. It also says "we have invested in optimizing merge queue operations, since that is key for repos that have many thousands of pull requests a day." The post does not tie either point to the April 23 regression.
On what customers see during an incident, GitHub says it recently updated its status page to include availability numbers, and has committed to statusing incidents both large and small, "so you do not have to guess whether an issue is on your side or ours."
What would have told a team that a completed merge had reverted earlier changes?
Sources
- GitHub. An update on GitHub availability. April 28, 2026. incident report