Regression issues occur when new code changes unintentionally break existing functionality. A developer might add a feature or fix a bug, only to cause another part of the system to stop working.

This problem typically arises from shared logic, modified dependencies, or configuration shifts. During refactoring, even minor alterations can introduce bugs that disrupt previously stable features.

Teams detect these issues through automated regression testing. These tests rerun existing test cases after each update, ensuring old functions still operate correctly within Continuous Integration pipelines.

Preventing regressions early saves time, money, and outages. Without proper testing, broken features can reach production, leading to user frustration and costly rollbacks. Modern CI tools integrate regression checks by default.