A bug you verified as fixed has come back in a later build. What do you do?
BugsMid-level
In shortConfirm it's really the same bug on the current build, reopen the original or report a new regression linked to it depending on the team's rules, add evidence and the build where it reappeared, and make sure a regression test exists so it can't silently return again.
Model answer
A fixed bug coming back is a regression: something that worked has broken again. It’s a useful signal, so I handle it carefully.
1. Confirm it’s really the same bug
I follow the original steps on the current build. Same symptom, same conditions? Sometimes it’s a similar bug with a different cause, for example the original fix covered iOS but this happens on Android.
2. Find when it came back
I check which builds have it. “Fixed in 3.4.0, still fine in 3.4.2, broken again in 3.5.0” helps the developer find the change that reintroduced it, often a merge, a refactor or a library update.
3. Reopen or create a new bug, following the team’s rules
- Many teams reopen the original if it’s the same bug and the original hasn’t been released yet.
- If the fix was already released, teams often create a new bug marked as a regression and linked to the original, so release history stays correct.
Either way, I add the new build number, evidence, and a link to the original fix.
4. Raise the priority if needed. A regression of something users already have working is often more urgent than a new bug.
5. Prevent it next time
- Make sure the scenario is in the regression suite, or ask for an automated test.
- In the retro, ask how it came back: missing unit test, a merge conflict, two branches fixing the same code?
Learn more: Bug Life Cycle
What they're looking for
Understanding of reopening vs a new linked bug, the idea of a regression, checking the build history to narrow down when it came back, and prevention through a regression test.
Common mistakes
- Assuming it's the same bug without checking the steps and cause.
- Creating a brand-new bug with no link to the original.
- Blaming the developer instead of asking how it was reintroduced.
- Not adding the bug's scenario to the regression suite.